Snap for 11933214 from 5d34f7ab34134d22f37d819d54f9f57f34b4ce62 to busytown-mac-infra-releasebusytown-mac-infra-release

Change-Id: I26cb63474bf93ef9785c303a2799f509e99de678

96 files changed, 4781 insertions, 1018 deletions

diff --git a/.github/workflows/code-check.yml b/.github/workflows/code-check.yml
index d65c650..37fb816 100644
--- a/.github/workflows/code-check.yml
+++ b/.github/workflows/code-check.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
       fail-fast: false
 
     steps:
@@ -33,7 +33,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        python -m pip install ".[build,test,development]"
+        python -m pip install ".[build,test,development,pandora]"
     - name: Check
       run: |
         invoke project.pre-commit
diff --git a/.github/workflows/python-avatar.yml b/.github/workflows/python-avatar.yml
index eb1b270..a7403a3 100644
--- a/.github/workflows/python-avatar.yml
+++ b/.github/workflows/python-avatar.yml
@@ -32,7 +32,7 @@ jobs:
       - name: Install
         run: |
           python -m pip install --upgrade pip
-          python -m pip install .[avatar]
+          python -m pip install .[avatar,pandora]
       - name: Rootcanal
         run: nohup python -m rootcanal > rootcanal.log &
       - name: Test
diff --git a/.github/workflows/python-build-test.yml b/.github/workflows/python-build-test.yml
index f1a8105..230779f 100644
--- a/.github/workflows/python-build-test.yml
+++ b/.github/workflows/python-build-test.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
-        python-version: ["3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
       fail-fast: false
 
     steps:
@@ -46,7 +46,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ "3.8", "3.9", "3.10", "3.11" ]
+        python-version: [ "3.8", "3.9", "3.10", "3.11", "3.12" ]
         rust-version: [ "1.76.0", "stable" ]
       fail-fast: false
     steps:
diff --git a/.gitignore b/.gitignore
index 1a5fb9d..ac9f74d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,8 @@ dist/
 docs/mkdocs/site
 test-results.xml
 __pycache__
+# Vim
+.*.sw*
 # generated by setuptools_scm
 bumble/_version.py
 .vscode/launch.json
diff --git a/.vscode/settings.json b/.vscode/settings.json
index b535ada..777c47b 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,6 +1,7 @@
 {
     "cSpell.words": [
         "Abortable",
+        "aiohttp",
         "altsetting",
         "ansiblue",
         "ansicyan",
@@ -9,6 +10,7 @@
         "ansired",
         "ansiyellow",
         "appendleft",
+        "ascs",
         "ASHA",
         "asyncio",
         "ATRAC",
@@ -43,6 +45,7 @@
         "keyup",
         "levelname",
         "libc",
+        "liblc",
         "libusb",
         "MITM",
         "MSBC",
@@ -78,6 +81,7 @@
         "unmuted",
         "usbmodem",
         "vhci",
+        "wasmtime",
         "websockets",
         "xcursor",
         "ycursor"
diff --git a/apps/bench.py b/apps/bench.py
index 83625f0..f0e8b58 100644
--- a/apps/bench.py
+++ b/apps/bench.py
@@ -509,9 +509,11 @@ class Ping:
         packet = struct.pack(
             '>bbI',
             PacketType.SEQUENCE,
-            PACKET_FLAG_LAST
-            if self.current_packet_index == self.tx_packet_count - 1
-            else 0,
+            (
+                PACKET_FLAG_LAST
+                if self.current_packet_index == self.tx_packet_count - 1
+                else 0
+            ),
             self.current_packet_index,
         ) + bytes(self.tx_packet_size - 6)
         logging.info(color(f'Sending packet {self.current_packet_index}', 'yellow'))
@@ -897,14 +899,26 @@ class L2capServer(StreamedPacketIO):
 # RfcommClient
 # -----------------------------------------------------------------------------
 class RfcommClient(StreamedPacketIO):
-    def __init__(self, device, channel, uuid, l2cap_mtu, max_frame_size, window_size):
+    def __init__(
+        self,
+        device,
+        channel,
+        uuid,
+        l2cap_mtu,
+        max_frame_size,
+        initial_credits,
+        max_credits,
+        credits_threshold,
+    ):
         super().__init__()
         self.device = device
         self.channel = channel
         self.uuid = uuid
         self.l2cap_mtu = l2cap_mtu
         self.max_frame_size = max_frame_size
-        self.window_size = window_size
+        self.initial_credits = initial_credits
+        self.max_credits = max_credits
+        self.credits_threshold = credits_threshold
         self.rfcomm_session = None
         self.ready = asyncio.Event()
 
@@ -938,12 +952,17 @@ class RfcommClient(StreamedPacketIO):
         logging.info(color(f'### Opening session for channel {channel}...', 'yellow'))
         try:
             dlc_options = {}
-            if self.max_frame_size:
+            if self.max_frame_size is not None:
                 dlc_options['max_frame_size'] = self.max_frame_size
-            if self.window_size:
-                dlc_options['window_size'] = self.window_size
+            if self.initial_credits is not None:
+                dlc_options['initial_credits'] = self.initial_credits
             rfcomm_session = await rfcomm_mux.open_dlc(channel, **dlc_options)
             logging.info(color(f'### Session open: {rfcomm_session}', 'yellow'))
+            if self.max_credits is not None:
+                rfcomm_session.rx_max_credits = self.max_credits
+            if self.credits_threshold is not None:
+                rfcomm_session.rx_credits_threshold = self.credits_threshold
+
         except bumble.core.ConnectionError as error:
             logging.info(color(f'!!! Session open failed: {error}', 'red'))
             await rfcomm_mux.disconnect()
@@ -967,8 +986,19 @@ class RfcommClient(StreamedPacketIO):
 # RfcommServer
 # -----------------------------------------------------------------------------
 class RfcommServer(StreamedPacketIO):
-    def __init__(self, device, channel, l2cap_mtu):
+    def __init__(
+        self,
+        device,
+        channel,
+        l2cap_mtu,
+        max_frame_size,
+        initial_credits,
+        max_credits,
+        credits_threshold,
+    ):
         super().__init__()
+        self.max_credits = max_credits
+        self.credits_threshold = credits_threshold
         self.dlc = None
         self.ready = asyncio.Event()
 
@@ -979,7 +1009,12 @@ class RfcommServer(StreamedPacketIO):
         rfcomm_server = bumble.rfcomm.Server(device, **server_options)
 
         # Listen for incoming DLC connections
-        channel_number = rfcomm_server.listen(self.on_dlc, channel)
+        dlc_options = {}
+        if max_frame_size is not None:
+            dlc_options['max_frame_size'] = max_frame_size
+        if initial_credits is not None:
+            dlc_options['initial_credits'] = initial_credits
+        channel_number = rfcomm_server.listen(self.on_dlc, channel, **dlc_options)
 
         # Setup the SDP to advertise this channel
         device.sdp_service_records = make_sdp_records(channel_number)
@@ -1002,6 +1037,10 @@ class RfcommServer(StreamedPacketIO):
         dlc.sink = self.on_packet
         self.io_sink = dlc.write
         self.dlc = dlc
+        if self.max_credits is not None:
+            dlc.rx_max_credits = self.max_credits
+        if self.credits_threshold is not None:
+            dlc.rx_credits_threshold = self.credits_threshold
 
     async def drain(self):
         assert self.dlc
@@ -1062,9 +1101,9 @@ class Central(Connection.Listener):
 
             if self.phy not in (None, HCI_LE_1M_PHY):
                 # Add an connections parameters entry for this PHY.
-                self.connection_parameter_preferences[
-                    self.phy
-                ] = connection_parameter_preferences
+                self.connection_parameter_preferences[self.phy] = (
+                    connection_parameter_preferences
+                )
         else:
             self.connection_parameter_preferences = None
 
@@ -1232,6 +1271,7 @@ class Peripheral(Device.Listener, Connection.Listener):
                         'cyan',
                     )
                 )
+
             await self.connected.wait()
             logging.info(color('### Connected', 'cyan'))
 
@@ -1318,7 +1358,9 @@ def create_mode_factory(ctx, default_mode):
                 uuid=ctx.obj['rfcomm_uuid'],
                 l2cap_mtu=ctx.obj['rfcomm_l2cap_mtu'],
                 max_frame_size=ctx.obj['rfcomm_max_frame_size'],
-                window_size=ctx.obj['rfcomm_window_size'],
+                initial_credits=ctx.obj['rfcomm_initial_credits'],
+                max_credits=ctx.obj['rfcomm_max_credits'],
+                credits_threshold=ctx.obj['rfcomm_credits_threshold'],
             )
 
         if mode == 'rfcomm-server':
@@ -1326,6 +1368,10 @@ def create_mode_factory(ctx, default_mode):
                 device,
                 channel=ctx.obj['rfcomm_channel'],
                 l2cap_mtu=ctx.obj['rfcomm_l2cap_mtu'],
+                max_frame_size=ctx.obj['rfcomm_max_frame_size'],
+                initial_credits=ctx.obj['rfcomm_initial_credits'],
+                max_credits=ctx.obj['rfcomm_max_credits'],
+                credits_threshold=ctx.obj['rfcomm_credits_threshold'],
             )
 
         raise ValueError('invalid mode')
@@ -1424,9 +1470,19 @@ def create_role_factory(ctx, default_role):
     help='RFComm maximum frame size',
 )
 @click.option(
-    '--rfcomm-window-size',
+    '--rfcomm-initial-credits',
+    type=int,
+    help='RFComm initial credits',
+)
+@click.option(
+    '--rfcomm-max-credits',
+    type=int,
+    help='RFComm max credits',
+)
+@click.option(
+    '--rfcomm-credits-threshold',
     type=int,
-    help='RFComm window size',
+    help='RFComm credits threshold',
 )
 @click.option(
     '--l2cap-psm',
@@ -1527,7 +1583,9 @@ def bench(
     rfcomm_uuid,
     rfcomm_l2cap_mtu,
     rfcomm_max_frame_size,
-    rfcomm_window_size,
+    rfcomm_initial_credits,
+    rfcomm_max_credits,
+    rfcomm_credits_threshold,
     l2cap_psm,
     l2cap_mtu,
     l2cap_mps,
@@ -1542,7 +1600,9 @@ def bench(
     ctx.obj['rfcomm_uuid'] = rfcomm_uuid
     ctx.obj['rfcomm_l2cap_mtu'] = rfcomm_l2cap_mtu
     ctx.obj['rfcomm_max_frame_size'] = rfcomm_max_frame_size
-    ctx.obj['rfcomm_window_size'] = rfcomm_window_size
+    ctx.obj['rfcomm_initial_credits'] = rfcomm_initial_credits
+    ctx.obj['rfcomm_max_credits'] = rfcomm_max_credits
+    ctx.obj['rfcomm_credits_threshold'] = rfcomm_credits_threshold
     ctx.obj['l2cap_psm'] = l2cap_psm
     ctx.obj['l2cap_mtu'] = l2cap_mtu
     ctx.obj['l2cap_mps'] = l2cap_mps
@@ -1591,8 +1651,8 @@ def central(
     mode_factory = create_mode_factory(ctx, 'gatt-client')
     classic = ctx.obj['classic']
 
-    asyncio.run(
-        Central(
+    async def run_central():
+        await Central(
             transport,
             peripheral_address,
             classic,
@@ -1604,7 +1664,8 @@ def central(
             encrypt or authenticate,
             ctx.obj['extended_data_length'],
         ).run()
-    )
+
+    asyncio.run(run_central())
 
 
 @bench.command()
@@ -1615,15 +1676,16 @@ def peripheral(ctx, transport):
     role_factory = create_role_factory(ctx, 'receiver')
     mode_factory = create_mode_factory(ctx, 'gatt-server')
 
-    asyncio.run(
-        Peripheral(
+    async def run_peripheral():
+        await Peripheral(
             transport,
             ctx.obj['classic'],
             ctx.obj['extended_data_length'],
             role_factory,
             mode_factory,
         ).run()
-    )
+
+    asyncio.run(run_peripheral())
 
 
 def main():
diff --git a/apps/lea_unicast/app.py b/apps/lea_unicast/app.py
new file mode 100644
index 0000000..ae3b442
--- /dev/null
+++ b/apps/lea_unicast/app.py
@@ -0,0 +1,577 @@
+# Copyright 2021-2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+import asyncio
+import datetime
+import enum
+import functools
+from importlib import resources
+import json
+import os
+import logging
+import pathlib
+from typing import Optional, List, cast
+import weakref
+import struct
+
+import ctypes
+import wasmtime
+import wasmtime.loader
+import liblc3  # type: ignore
+import logging
+
+import click
+import aiohttp.web
+
+import bumble
+from bumble.core import AdvertisingData
+from bumble.colors import color
+from bumble.device import Device, DeviceConfiguration, AdvertisingParameters
+from bumble.transport import open_transport
+from bumble.profiles import bap
+from bumble.hci import Address, CodecID, CodingFormat, HCI_IsoDataPacket
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+DEFAULT_UI_PORT = 7654
+
+
+def _sink_pac_record() -> bap.PacRecord:
+    return bap.PacRecord(
+        coding_format=CodingFormat(CodecID.LC3),
+        codec_specific_capabilities=bap.CodecSpecificCapabilities(
+            supported_sampling_frequencies=(
+                bap.SupportedSamplingFrequency.FREQ_8000
+                | bap.SupportedSamplingFrequency.FREQ_16000
+                | bap.SupportedSamplingFrequency.FREQ_24000
+                | bap.SupportedSamplingFrequency.FREQ_32000
+                | bap.SupportedSamplingFrequency.FREQ_48000
+            ),
+            supported_frame_durations=(
+                bap.SupportedFrameDuration.DURATION_10000_US_SUPPORTED
+            ),
+            supported_audio_channel_count=[1, 2],
+            min_octets_per_codec_frame=26,
+            max_octets_per_codec_frame=240,
+            supported_max_codec_frames_per_sdu=2,
+        ),
+    )
+
+
+def _source_pac_record() -> bap.PacRecord:
+    return bap.PacRecord(
+        coding_format=CodingFormat(CodecID.LC3),
+        codec_specific_capabilities=bap.CodecSpecificCapabilities(
+            supported_sampling_frequencies=(
+                bap.SupportedSamplingFrequency.FREQ_8000
+                | bap.SupportedSamplingFrequency.FREQ_16000
+                | bap.SupportedSamplingFrequency.FREQ_24000
+                | bap.SupportedSamplingFrequency.FREQ_32000
+                | bap.SupportedSamplingFrequency.FREQ_48000
+            ),
+            supported_frame_durations=(
+                bap.SupportedFrameDuration.DURATION_10000_US_SUPPORTED
+            ),
+            supported_audio_channel_count=[1],
+            min_octets_per_codec_frame=30,
+            max_octets_per_codec_frame=100,
+            supported_max_codec_frames_per_sdu=1,
+        ),
+    )
+
+
+# -----------------------------------------------------------------------------
+# WASM - liblc3
+# -----------------------------------------------------------------------------
+store = wasmtime.loader.store
+_memory = cast(wasmtime.Memory, liblc3.memory)
+STACK_POINTER = _memory.data_len(store)
+_memory.grow(store, 1)
+# Mapping wasmtime memory to linear address
+memory = (ctypes.c_ubyte * _memory.data_len(store)).from_address(
+    ctypes.addressof(_memory.data_ptr(store).contents)  # type: ignore
+)
+
+
+class Liblc3PcmFormat(enum.IntEnum):
+    S16 = 0
+    S24 = 1
+    S24_3LE = 2
+    FLOAT = 3
+
+
+MAX_DECODER_SIZE = liblc3.lc3_decoder_size(10000, 48000)
+MAX_ENCODER_SIZE = liblc3.lc3_encoder_size(10000, 48000)
+
+DECODER_STACK_POINTER = STACK_POINTER
+ENCODER_STACK_POINTER = DECODER_STACK_POINTER + MAX_DECODER_SIZE * 2
+DECODE_BUFFER_STACK_POINTER = ENCODER_STACK_POINTER + MAX_ENCODER_SIZE * 2
+ENCODE_BUFFER_STACK_POINTER = DECODE_BUFFER_STACK_POINTER + 8192
+DEFAULT_PCM_SAMPLE_RATE = 48000
+DEFAULT_PCM_FORMAT = Liblc3PcmFormat.S16
+DEFAULT_PCM_BYTES_PER_SAMPLE = 2
+
+
+encoders: List[int] = []
+decoders: List[int] = []
+
+
+def setup_encoders(
+    sample_rate_hz: int, frame_duration_us: int, num_channels: int
+) -> None:
+    logger.info(
+        f"setup_encoders {sample_rate_hz}Hz {frame_duration_us}us {num_channels}channels"
+    )
+    encoders[:num_channels] = [
+        liblc3.lc3_setup_encoder(
+            frame_duration_us,
+            sample_rate_hz,
+            DEFAULT_PCM_SAMPLE_RATE,  # Input sample rate
+            ENCODER_STACK_POINTER + MAX_ENCODER_SIZE * i,
+        )
+        for i in range(num_channels)
+    ]
+
+
+def setup_decoders(
+    sample_rate_hz: int, frame_duration_us: int, num_channels: int
+) -> None:
+    logger.info(
+        f"setup_decoders {sample_rate_hz}Hz {frame_duration_us}us {num_channels}channels"
+    )
+    decoders[:num_channels] = [
+        liblc3.lc3_setup_decoder(
+            frame_duration_us,
+            sample_rate_hz,
+            DEFAULT_PCM_SAMPLE_RATE,  # Output sample rate
+            DECODER_STACK_POINTER + MAX_DECODER_SIZE * i,
+        )
+        for i in range(num_channels)
+    ]
+
+
+def decode(
+    frame_duration_us: int,
+    num_channels: int,
+    input_bytes: bytes,
+) -> bytes:
+    if not input_bytes:
+        return b''
+
+    input_buffer_offset = DECODE_BUFFER_STACK_POINTER
+    input_buffer_size = len(input_bytes)
+    input_bytes_per_frame = input_buffer_size // num_channels
+
+    # Copy into wasm
+    memory[input_buffer_offset : input_buffer_offset + input_buffer_size] = input_bytes  # type: ignore
+
+    output_buffer_offset = input_buffer_offset + input_buffer_size
+    output_buffer_size = (
+        liblc3.lc3_frame_samples(frame_duration_us, DEFAULT_PCM_SAMPLE_RATE)
+        * DEFAULT_PCM_BYTES_PER_SAMPLE
+        * num_channels
+    )
+
+    for i in range(num_channels):
+        res = liblc3.lc3_decode(
+            decoders[i],
+            input_buffer_offset + input_bytes_per_frame * i,
+            input_bytes_per_frame,
+            DEFAULT_PCM_FORMAT,
+            output_buffer_offset + i * DEFAULT_PCM_BYTES_PER_SAMPLE,
+            num_channels,  # Stride
+        )
+
+        if res != 0:
+            logging.error(f"Parsing failed, res={res}")
+
+    # Extract decoded data from the output buffer
+    return bytes(
+        memory[output_buffer_offset : output_buffer_offset + output_buffer_size]
+    )
+
+
+def encode(
+    sdu_length: int,
+    num_channels: int,
+    stride: int,
+    input_bytes: bytes,
+) -> bytes:
+    if not input_bytes:
+        return b''
+
+    input_buffer_offset = ENCODE_BUFFER_STACK_POINTER
+    input_buffer_size = len(input_bytes)
+
+    # Copy into wasm
+    memory[input_buffer_offset : input_buffer_offset + input_buffer_size] = input_bytes  # type: ignore
+
+    output_buffer_offset = input_buffer_offset + input_buffer_size
+    output_buffer_size = sdu_length
+    output_frame_size = output_buffer_size // num_channels
+
+    for i in range(num_channels):
+        res = liblc3.lc3_encode(
+            encoders[i],
+            DEFAULT_PCM_FORMAT,
+            input_buffer_offset + DEFAULT_PCM_BYTES_PER_SAMPLE * i,
+            stride,
+            output_frame_size,
+            output_buffer_offset + output_frame_size * i,
+        )
+
+        if res != 0:
+            logging.error(f"Parsing failed, res={res}")
+
+    # Extract decoded data from the output buffer
+    return bytes(
+        memory[output_buffer_offset : output_buffer_offset + output_buffer_size]
+    )
+
+
+async def lc3_source_task(
+    filename: str,
+    sdu_length: int,
+    frame_duration_us: int,
+    device: Device,
+    cis_handle: int,
+) -> None:
+    with open(filename, 'rb') as f:
+        header = f.read(44)
+        assert header[8:12] == b'WAVE'
+
+        pcm_num_channel, pcm_sample_rate, _byte_rate, _block_align, bits_per_sample = (
+            struct.unpack("<HIIHH", header[22:36])
+        )
+        assert pcm_sample_rate == DEFAULT_PCM_SAMPLE_RATE
+        assert bits_per_sample == DEFAULT_PCM_BYTES_PER_SAMPLE * 8
+
+        frame_bytes = (
+            liblc3.lc3_frame_samples(frame_duration_us, DEFAULT_PCM_SAMPLE_RATE)
+            * DEFAULT_PCM_BYTES_PER_SAMPLE
+        )
+        packet_sequence_number = 0
+
+        while True:
+            next_round = datetime.datetime.now() + datetime.timedelta(
+                microseconds=frame_duration_us
+            )
+            pcm_data = f.read(frame_bytes)
+            sdu = encode(sdu_length, pcm_num_channel, pcm_num_channel, pcm_data)
+
+            iso_packet = HCI_IsoDataPacket(
+                connection_handle=cis_handle,
+                data_total_length=sdu_length + 4,
+                packet_sequence_number=packet_sequence_number,
+                pb_flag=0b10,
+                packet_status_flag=0,
+                iso_sdu_length=sdu_length,
+                iso_sdu_fragment=sdu,
+            )
+            device.host.send_hci_packet(iso_packet)
+            packet_sequence_number += 1
+            sleep_time = next_round - datetime.datetime.now()
+            await asyncio.sleep(sleep_time.total_seconds())
+
+
+# -----------------------------------------------------------------------------
+class UiServer:
+    speaker: weakref.ReferenceType[Speaker]
+    port: int
+
+    def __init__(self, speaker: Speaker, port: int) -> None:
+        self.speaker = weakref.ref(speaker)
+        self.port = port
+        self.channel_socket = None
+
+    async def start_http(self) -> None:
+        """Start the UI HTTP server."""
+
+        app = aiohttp.web.Application()
+        app.add_routes(
+            [
+                aiohttp.web.get('/', self.get_static),
+                aiohttp.web.get('/index.html', self.get_static),
+                aiohttp.web.get('/channel', self.get_channel),
+            ]
+        )
+
+        runner = aiohttp.web.AppRunner(app)
+        await runner.setup()
+        site = aiohttp.web.TCPSite(runner, 'localhost', self.port)
+        print('UI HTTP server at ' + color(f'http://127.0.0.1:{self.port}', 'green'))
+        await site.start()
+
+    async def get_static(self, request):
+        path = request.path
+        if path == '/':
+            path = '/index.html'
+        if path.endswith('.html'):
+            content_type = 'text/html'
+        elif path.endswith('.js'):
+            content_type = 'text/javascript'
+        elif path.endswith('.css'):
+            content_type = 'text/css'
+        elif path.endswith('.svg'):
+            content_type = 'image/svg+xml'
+        else:
+            content_type = 'text/plain'
+        text = (
+            resources.files("bumble.apps.lea_unicast")
+            .joinpath(pathlib.Path(path).relative_to('/'))
+            .read_text(encoding="utf-8")
+        )
+        return aiohttp.web.Response(text=text, content_type=content_type)
+
+    async def get_channel(self, request):
+        ws = aiohttp.web.WebSocketResponse()
+        await ws.prepare(request)
+
+        # Process messages until the socket is closed.
+        self.channel_socket = ws
+        async for message in ws:
+            if message.type == aiohttp.WSMsgType.TEXT:
+                logger.debug(f'<<< received message: {message.data}')
+                await self.on_message(message.data)
+            elif message.type == aiohttp.WSMsgType.ERROR:
+                logger.debug(
+                    f'channel connection closed with exception {ws.exception()}'
+                )
+
+        self.channel_socket = None
+        logger.debug('--- channel connection closed')
+
+        return ws
+
+    async def on_message(self, message_str: str):
+        # Parse the message as JSON
+        message = json.loads(message_str)
+
+        # Dispatch the message
+        message_type = message['type']
+        message_params = message.get('params', {})
+        handler = getattr(self, f'on_{message_type}_message')
+        if handler:
+            await handler(**message_params)
+
+    async def on_hello_message(self):
+        await self.send_message(
+            'hello',
+            bumble_version=bumble.__version__,
+            codec=self.speaker().codec,
+            streamState=self.speaker().stream_state.name,
+        )
+        if connection := self.speaker().connection:
+            await self.send_message(
+                'connection',
+                peer_address=connection.peer_address.to_string(False),
+                peer_name=connection.peer_name,
+            )
+
+    async def send_message(self, message_type: str, **kwargs) -> None:
+        if self.channel_socket is None:
+            return
+
+        message = {'type': message_type, 'params': kwargs}
+        await self.channel_socket.send_json(message)
+
+    async def send_audio(self, data: bytes) -> None:
+        if self.channel_socket is None:
+            return
+
+        try:
+            await self.channel_socket.send_bytes(data)
+        except Exception as error:
+            logger.warning(f'exception while sending audio packet: {error}')
+
+
+# -----------------------------------------------------------------------------
+class Speaker:
+
+    def __init__(
+        self,
+        device_config_path: Optional[str],
+        ui_port: int,
+        transport: str,
+        lc3_input_file_path: str,
+    ):
+        self.device_config_path = device_config_path
+        self.transport = transport
+        self.lc3_input_file_path = lc3_input_file_path
+
+        # Create an HTTP server for the UI
+        self.ui_server = UiServer(speaker=self, port=ui_port)
+
+    async def run(self) -> None:
+        await self.ui_server.start_http()
+
+        async with await open_transport(self.transport) as hci_transport:
+            # Create a device
+            if self.device_config_path:
+                device_config = DeviceConfiguration.from_file(self.device_config_path)
+            else:
+                device_config = DeviceConfiguration(
+                    name="Bumble LE Headphone",
+                    class_of_device=0x244418,
+                    keystore="JsonKeyStore",
+                    advertising_interval_min=25,
+                    advertising_interval_max=25,
+                    address=Address('F1:F2:F3:F4:F5:F6'),
+                )
+
+            device_config.le_enabled = True
+            device_config.cis_enabled = True
+            self.device = Device.from_config_with_hci(
+                device_config, hci_transport.source, hci_transport.sink
+            )
+
+            self.device.add_service(
+                bap.PublishedAudioCapabilitiesService(
+                    supported_source_context=bap.ContextType(0xFFFF),
+                    available_source_context=bap.ContextType(0xFFFF),
+                    supported_sink_context=bap.ContextType(0xFFFF),  # All context types
+                    available_sink_context=bap.ContextType(0xFFFF),  # All context types
+                    sink_audio_locations=(
+                        bap.AudioLocation.FRONT_LEFT | bap.AudioLocation.FRONT_RIGHT
+                    ),
+                    sink_pac=[_sink_pac_record()],
+                    source_audio_locations=bap.AudioLocation.FRONT_LEFT,
+                    source_pac=[_source_pac_record()],
+                )
+            )
+
+            ascs = bap.AudioStreamControlService(
+                self.device, sink_ase_id=[1], source_ase_id=[2]
+            )
+            self.device.add_service(ascs)
+
+            advertising_data = bytes(
+                AdvertisingData(
+                    [
+                        (
+                            AdvertisingData.COMPLETE_LOCAL_NAME,
+                            bytes(device_config.name, 'utf-8'),
+                        ),
+                        (
+                            AdvertisingData.FLAGS,
+                            bytes([AdvertisingData.LE_GENERAL_DISCOVERABLE_MODE_FLAG]),
+                        ),
+                        (
+                            AdvertisingData.INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS,
+                            bytes(bap.PublishedAudioCapabilitiesService.UUID),
+                        ),
+                    ]
+                )
+            ) + bytes(bap.UnicastServerAdvertisingData())
+
+            def on_pdu(pdu: HCI_IsoDataPacket, ase: bap.AseStateMachine):
+                codec_config = ase.codec_specific_configuration
+                assert isinstance(codec_config, bap.CodecSpecificConfiguration)
+                pcm = decode(
+                    codec_config.frame_duration.us,
+                    codec_config.audio_channel_allocation.channel_count,
+                    pdu.iso_sdu_fragment,
+                )
+                self.device.abort_on('disconnection', self.ui_server.send_audio(pcm))
+
+            def on_ase_state_change(ase: bap.AseStateMachine) -> None:
+                if ase.state == bap.AseStateMachine.State.STREAMING:
+                    codec_config = ase.codec_specific_configuration
+                    assert isinstance(codec_config, bap.CodecSpecificConfiguration)
+                    assert ase.cis_link
+                    if ase.role == bap.AudioRole.SOURCE:
+                        ase.cis_link.abort_on(
+                            'disconnection',
+                            lc3_source_task(
+                                filename=self.lc3_input_file_path,
+                                sdu_length=(
+                                    codec_config.codec_frames_per_sdu
+                                    * codec_config.octets_per_codec_frame
+                                ),
+                                frame_duration_us=codec_config.frame_duration.us,
+                                device=self.device,
+                                cis_handle=ase.cis_link.handle,
+                            ),
+                        )
+                    else:
+                        ase.cis_link.sink = functools.partial(on_pdu, ase=ase)
+                elif ase.state == bap.AseStateMachine.State.CODEC_CONFIGURED:
+                    codec_config = ase.codec_specific_configuration
+                    assert isinstance(codec_config, bap.CodecSpecificConfiguration)
+                    if ase.role == bap.AudioRole.SOURCE:
+                        setup_encoders(
+                            codec_config.sampling_frequency.hz,
+                            codec_config.frame_duration.us,
+                            codec_config.audio_channel_allocation.channel_count,
+                        )
+                    else:
+                        setup_decoders(
+                            codec_config.sampling_frequency.hz,
+                            codec_config.frame_duration.us,
+                            codec_config.audio_channel_allocation.channel_count,
+                        )
+
+            for ase in ascs.ase_state_machines.values():
+                ase.on('state_change', functools.partial(on_ase_state_change, ase=ase))
+
+            await self.device.power_on()
+            await self.device.create_advertising_set(
+                advertising_data=advertising_data,
+                auto_restart=True,
+                advertising_parameters=AdvertisingParameters(
+                    primary_advertising_interval_min=100,
+                    primary_advertising_interval_max=100,
+                ),
+            )
+
+            await hci_transport.source.terminated
+
+
+@click.command()
+@click.option(
+    '--ui-port',
+    'ui_port',
+    metavar='HTTP_PORT',
+    default=DEFAULT_UI_PORT,
+    show_default=True,
+    help='HTTP port for the UI server',
+)
+@click.option('--device-config', metavar='FILENAME', help='Device configuration file')
+@click.argument('transport')
+@click.argument('lc3_file')
+def speaker(ui_port: int, device_config: str, transport: str, lc3_file: str) -> None:
+    """Run the speaker."""
+
+    asyncio.run(Speaker(device_config, ui_port, transport, lc3_file).run())
+
+
+# -----------------------------------------------------------------------------
+def main():
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'WARNING').upper())
+    speaker()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == "__main__":
+    main()  # pylint: disable=no-value-for-parameter
diff --git a/apps/lea_unicast/index.html b/apps/lea_unicast/index.html
new file mode 100644
index 0000000..fb1e61c
--- /dev/null
+++ b/apps/lea_unicast/index.html
@@ -0,0 +1,68 @@
+<html data-bs-theme="dark">
+
+<head>
+    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet"
+        integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous">
+    <script src="https://unpkg.com/pcm-player"></script>
+</head>
+
+<body>
+    <nav class="navbar navbar-dark bg-primary">
+        <div class="container">
+            <span class="navbar-brand mb-0 h1">Bumble Unicast Server</span>
+        </div>
+    </nav>
+    <br>
+
+    <div class="container">
+        <button type="button" class="btn btn-danger" id="connect-audio" onclick="connectAudio()">Connect Audio</button>
+        <button class="btn btn-primary" type="button" disabled>
+            <span class="spinner-border spinner-border-sm" id="ws-status-spinner" aria-hidden="true"></span>
+            <span role="status" id="ws-status">WebSocket Connecting...</span>
+        </button>
+    </div>
+
+
+    <script>
+        let player = null;
+        const wsStatus = document.getElementById("ws-status");
+        const wsStatusSpinner = document.getElementById("ws-status-spinner");
+
+        const socket = new WebSocket('ws://127.0.0.1:7654/channel');
+        socket.binaryType = "arraybuffer";
+        socket.onmessage = function (message) {
+            if (typeof message.data === 'string' || message.data instanceof String) {
+                console.log(`channel MESSAGE: ${message.data}`);
+            } else {
+                console.log(typeof (message.data))
+                // BINARY audio data.
+                if (player == null) return;
+                player.feed(message.data);
+            }
+        };
+
+        socket.onopen = (message) => {
+            wsStatusSpinner.remove();
+            wsStatus.textContent = "WebSocket Connected";
+        }
+
+        socket.onclose = (message) => {
+            wsStatus.textContent = "WebSocket Disconnected";
+        }
+
+        function connectAudio() {
+            player = new PCMPlayer({
+                inputCodec: 'Int16',
+                channels: 2,
+                sampleRate: 48000,
+                flushTime: 10,
+            });
+            const button = document.getElementById("connect-audio")
+            button.disabled = true;
+            button.textContent = "Audio Connected";
+        }
+    </script>
+    </div>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/apps/lea_unicast/liblc3.wasm b/apps/lea_unicast/liblc3.wasm
new file mode 100755
index 0000000..e905105
--- /dev/null
+++ b/apps/lea_unicast/liblc3.wasm
diff --git a/apps/rfcomm_bridge.py b/apps/rfcomm_bridge.py
new file mode 100644
index 0000000..728e7cf
--- /dev/null
+++ b/apps/rfcomm_bridge.py
@@ -0,0 +1,511 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import asyncio
+import logging
+import os
+import time
+from typing import Optional
+
+import click
+
+from bumble.colors import color
+from bumble.device import Device, DeviceConfiguration, Connection
+from bumble import core
+from bumble import hci
+from bumble import rfcomm
+from bumble import transport
+from bumble import utils
+
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+DEFAULT_RFCOMM_UUID = "E6D55659-C8B4-4B85-96BB-B1143AF6D3AE"
+DEFAULT_MTU = 4096
+DEFAULT_CLIENT_TCP_PORT = 9544
+DEFAULT_SERVER_TCP_PORT = 9545
+
+TRACE_MAX_SIZE = 48
+
+
+# -----------------------------------------------------------------------------
+class Tracer:
+    """
+    Trace data buffers transmitted from one endpoint to another, with stats.
+    """
+
+    def __init__(self, channel_name: str) -> None:
+        self.channel_name = channel_name
+        self.last_ts: float = 0.0
+
+    def trace_data(self, data: bytes) -> None:
+        now = time.time()
+        elapsed_s = now - self.last_ts if self.last_ts else 0
+        elapsed_ms = int(elapsed_s * 1000)
+        instant_throughput_kbps = ((len(data) / elapsed_s) / 1000) if elapsed_s else 0.0
+
+        hex_str = data[:TRACE_MAX_SIZE].hex() + (
+            "..." if len(data) > TRACE_MAX_SIZE else ""
+        )
+        print(
+            f"[{self.channel_name}] {len(data):4} bytes "
+            f"(+{elapsed_ms:4}ms, {instant_throughput_kbps: 7.2f}kB/s) "
+            f" {hex_str}"
+        )
+
+        self.last_ts = now
+
+
+# -----------------------------------------------------------------------------
+class ServerBridge:
+    """
+    RFCOMM server bridge: waits for a peer to connect an RFCOMM channel.
+    The RFCOMM channel may be associated with a UUID published in an SDP service
+    description, or simply be on a system-assigned channel number.
+    When the connection is made, the bridge connects a TCP socket to a remote host and
+    bridges the data in both directions, with flow control.
+    When the RFCOMM channel is closed, the bridge disconnects the TCP socket
+    and waits for a new channel to be connected.
+    """
+
+    READ_CHUNK_SIZE = 4096
+
+    def __init__(
+        self, channel: int, uuid: str, trace: bool, tcp_host: str, tcp_port: int
+    ) -> None:
+        self.device: Optional[Device] = None
+        self.channel = channel
+        self.uuid = uuid
+        self.tcp_host = tcp_host
+        self.tcp_port = tcp_port
+        self.rfcomm_channel: Optional[rfcomm.DLC] = None
+        self.tcp_tracer: Optional[Tracer]
+        self.rfcomm_tracer: Optional[Tracer]
+
+        if trace:
+            self.tcp_tracer = Tracer(color("RFCOMM->TCP", "cyan"))
+            self.rfcomm_tracer = Tracer(color("TCP->RFCOMM", "magenta"))
+        else:
+            self.rfcomm_tracer = None
+            self.tcp_tracer = None
+
+    async def start(self, device: Device) -> None:
+        self.device = device
+
+        # Create and register a server
+        rfcomm_server = rfcomm.Server(self.device)
+
+        # Listen for incoming DLC connections
+        self.channel = rfcomm_server.listen(self.on_rfcomm_channel, self.channel)
+
+        # Setup the SDP to advertise this channel
+        service_record_handle = 0x00010001
+        self.device.sdp_service_records = {
+            service_record_handle: rfcomm.make_service_sdp_records(
+                service_record_handle, self.channel, core.UUID(self.uuid)
+            )
+        }
+
+        # We're ready for a connection
+        self.device.on("connection", self.on_connection)
+        await self.set_available(True)
+
+        print(
+            color(
+                (
+                    f"### Listening for RFCOMM connection on {device.public_address}, "
+                    f"channel {self.channel}"
+                ),
+                "yellow",
+            )
+        )
+
+    async def set_available(self, available: bool):
+        # Become discoverable and connectable
+        assert self.device
+        await self.device.set_connectable(available)
+        await self.device.set_discoverable(available)
+
+    def on_connection(self, connection):
+        print(color(f"@@@ Bluetooth connection: {connection}", "blue"))
+        connection.on("disconnection", self.on_disconnection)
+
+        # Don't accept new connections until we're disconnected
+        utils.AsyncRunner.spawn(self.set_available(False))
+
+    def on_disconnection(self, reason: int):
+        print(
+            color("@@@ Bluetooth disconnection:", "red"),
+            hci.HCI_Constant.error_name(reason),
+        )
+
+        # We're ready for a new connection
+        utils.AsyncRunner.spawn(self.set_available(True))
+
+    # Called when an RFCOMM channel is established
+    @utils.AsyncRunner.run_in_task()
+    async def on_rfcomm_channel(self, rfcomm_channel):
+        print(color("*** RFCOMM channel:", "cyan"), rfcomm_channel)
+
+        # Connect to the TCP server
+        print(
+            color(
+                f"### Connecting to TCP {self.tcp_host}:{self.tcp_port}",
+                "yellow",
+            )
+        )
+        try:
+            reader, writer = await asyncio.open_connection(self.tcp_host, self.tcp_port)
+        except OSError:
+            print(color("!!! Connection failed", "red"))
+            await rfcomm_channel.disconnect()
+            return
+
+        # Pipe data from RFCOMM to TCP
+        def on_rfcomm_channel_closed():
+            print(color("*** RFCOMM channel closed", "cyan"))
+            writer.close()
+
+        def write_rfcomm_data(data):
+            if self.rfcomm_tracer:
+                self.rfcomm_tracer.trace_data(data)
+
+            writer.write(data)
+
+        rfcomm_channel.sink = write_rfcomm_data
+        rfcomm_channel.on("close", on_rfcomm_channel_closed)
+
+        # Pipe data from TCP to RFCOMM
+        while True:
+            try:
+                data = await reader.read(self.READ_CHUNK_SIZE)
+
+                if len(data) == 0:
+                    print(color("### TCP end of stream", "yellow"))
+                    if rfcomm_channel.state == rfcomm.DLC.State.CONNECTED:
+                        await rfcomm_channel.disconnect()
+                    return
+
+                if self.tcp_tracer:
+                    self.tcp_tracer.trace_data(data)
+
+                rfcomm_channel.write(data)
+                await rfcomm_channel.drain()
+            except Exception as error:
+                print(f"!!! Exception: {error}")
+                break
+
+        writer.close()
+        await writer.wait_closed()
+        print(color("~~~ Bye bye", "magenta"))
+
+
+# -----------------------------------------------------------------------------
+class ClientBridge:
+    """
+    RFCOMM client bridge: connects to a BR/EDR device, then waits for an inbound
+    TCP connection on a specified port number. When a TCP client connects, an
+    RFCOMM connection to the device is established, and the data is bridged in both
+    directions, with flow control.
+    When the TCP connection is closed by the client, the RFCOMM channel is
+    disconnected, but the connection to the device remains, ready for a new TCP client
+    to connect.
+    """
+
+    READ_CHUNK_SIZE = 4096
+
+    def __init__(
+        self,
+        channel: int,
+        uuid: str,
+        trace: bool,
+        address: str,
+        tcp_host: str,
+        tcp_port: int,
+        encrypt: bool,
+    ):
+        self.channel = channel
+        self.uuid = uuid
+        self.trace = trace
+        self.address = address
+        self.tcp_host = tcp_host
+        self.tcp_port = tcp_port
+        self.encrypt = encrypt
+        self.device: Optional[Device] = None
+        self.connection: Optional[Connection] = None
+        self.rfcomm_client: Optional[rfcomm.Client]
+        self.rfcomm_mux: Optional[rfcomm.Multiplexer]
+        self.tcp_connected: bool = False
+
+        self.tcp_tracer: Optional[Tracer]
+        self.rfcomm_tracer: Optional[Tracer]
+
+        if trace:
+            self.tcp_tracer = Tracer(color("RFCOMM->TCP", "cyan"))
+            self.rfcomm_tracer = Tracer(color("TCP->RFCOMM", "magenta"))
+        else:
+            self.rfcomm_tracer = None
+            self.tcp_tracer = None
+
+    async def connect(self) -> None:
+        if self.connection:
+            return
+
+        print(color(f"@@@ Connecting to Bluetooth {self.address}", "blue"))
+        assert self.device
+        self.connection = await self.device.connect(
+            self.address, transport=core.BT_BR_EDR_TRANSPORT
+        )
+        print(color(f"@@@ Bluetooth connection: {self.connection}", "blue"))
+        self.connection.on("disconnection", self.on_disconnection)
+
+        if self.encrypt:
+            print(color("@@@ Encrypting Bluetooth connection", "blue"))
+            await self.connection.encrypt()
+            print(color("@@@ Bluetooth connection encrypted", "blue"))
+
+        self.rfcomm_client = rfcomm.Client(self.connection)
+        try:
+            self.rfcomm_mux = await self.rfcomm_client.start()
+        except BaseException as e:
+            print(color("!!! Failed to setup RFCOMM connection", "red"), e)
+            raise
+
+    async def start(self, device: Device) -> None:
+        self.device = device
+        await device.set_connectable(False)
+        await device.set_discoverable(False)
+
+        # Called when a TCP connection is established
+        async def on_tcp_connection(reader, writer):
+            print(color("<<< TCP connection", "magenta"))
+            if self.tcp_connected:
+                print(
+                    color("!!! TCP connection already active, rejecting new one", "red")
+                )
+                writer.close()
+                return
+            self.tcp_connected = True
+
+            try:
+                await self.pipe(reader, writer)
+            except BaseException as error:
+                print(color("!!! Exception while piping data:", "red"), error)
+                return
+            finally:
+                writer.close()
+                await writer.wait_closed()
+                self.tcp_connected = False
+
+        await asyncio.start_server(
+            on_tcp_connection,
+            host=self.tcp_host if self.tcp_host != "_" else None,
+            port=self.tcp_port,
+        )
+        print(
+            color(
+                f"### Listening for TCP connections on port {self.tcp_port}", "magenta"
+            )
+        )
+
+    async def pipe(
+        self, reader: asyncio.StreamReader, writer: asyncio.StreamWriter
+    ) -> None:
+        # Resolve the channel number from the UUID if needed
+        if self.channel == 0:
+            await self.connect()
+            assert self.connection
+            channel = await rfcomm.find_rfcomm_channel_with_uuid(
+                self.connection, self.uuid
+            )
+            if channel:
+                print(color(f"### Found RFCOMM channel {channel}", "yellow"))
+            else:
+                print(color(f"!!! RFCOMM channel with UUID {self.uuid} not found"))
+                return
+        else:
+            channel = self.channel
+
+        # Connect a new RFCOMM channel
+        await self.connect()
+        assert self.rfcomm_mux
+        print(color(f"*** Opening RFCOMM channel {channel}", "green"))
+        try:
+            rfcomm_channel = await self.rfcomm_mux.open_dlc(channel)
+            print(color(f"*** RFCOMM channel open: {rfcomm_channel}", "green"))
+        except Exception as error:
+            print(color(f"!!! RFCOMM open failed: {error}", "red"))
+            return
+
+        # Pipe data from RFCOMM to TCP
+        def on_rfcomm_channel_closed():
+            print(color("*** RFCOMM channel closed", "green"))
+
+        def write_rfcomm_data(data):
+            if self.trace:
+                self.rfcomm_tracer.trace_data(data)
+
+            writer.write(data)
+
+        rfcomm_channel.on("close", on_rfcomm_channel_closed)
+        rfcomm_channel.sink = write_rfcomm_data
+
+        # Pipe data from TCP to RFCOMM
+        while True:
+            try:
+                data = await reader.read(self.READ_CHUNK_SIZE)
+
+                if len(data) == 0:
+                    print(color("### TCP end of stream", "yellow"))
+                    if rfcomm_channel.state == rfcomm.DLC.State.CONNECTED:
+                        await rfcomm_channel.disconnect()
+                    self.tcp_connected = False
+                    return
+
+                if self.tcp_tracer:
+                    self.tcp_tracer.trace_data(data)
+
+                rfcomm_channel.write(data)
+                await rfcomm_channel.drain()
+            except Exception as error:
+                print(f"!!! Exception: {error}")
+                break
+
+        print(color("~~~ Bye bye", "magenta"))
+
+    def on_disconnection(self, reason: int) -> None:
+        print(
+            color("@@@ Bluetooth disconnection:", "red"),
+            hci.HCI_Constant.error_name(reason),
+        )
+        self.connection = None
+
+
+# -----------------------------------------------------------------------------
+async def run(device_config, hci_transport, bridge):
+    print("<<< connecting to HCI...")
+    async with await transport.open_transport_or_link(hci_transport) as (
+        hci_source,
+        hci_sink,
+    ):
+        print("<<< connected")
+
+        if device_config:
+            device = Device.from_config_file_with_hci(
+                device_config, hci_source, hci_sink
+            )
+        else:
+            device = Device.from_config_with_hci(
+                DeviceConfiguration(), hci_source, hci_sink
+            )
+        device.classic_enabled = True
+
+        # Let's go
+        await device.power_on()
+        try:
+            await bridge.start(device)
+
+            # Wait until the transport terminates
+            await hci_source.wait_for_termination()
+        except core.ConnectionError as error:
+            print(color(f"!!! Bluetooth connection failed: {error}", "red"))
+        except Exception as error:
+            print(f"Exception while running bridge: {error}")
+
+
+# -----------------------------------------------------------------------------
+@click.group()
+@click.pass_context
+@click.option(
+    "--device-config",
+    metavar="CONFIG_FILE",
+    help="Device configuration file",
+)
+@click.option(
+    "--hci-transport", metavar="TRANSPORT_NAME", help="HCI transport", required=True
+)
+@click.option("--trace", is_flag=True, help="Trace bridged data to stdout")
+@click.option(
+    "--channel",
+    metavar="CHANNEL_NUMER",
+    help="RFCOMM channel number",
+    type=int,
+    default=0,
+)
+@click.option(
+    "--uuid",
+    metavar="UUID",
+    help="UUID for the RFCOMM channel",
+    default=DEFAULT_RFCOMM_UUID,
+)
+def cli(
+    context,
+    device_config,
+    hci_transport,
+    trace,
+    channel,
+    uuid,
+):
+    context.ensure_object(dict)
+    context.obj["device_config"] = device_config
+    context.obj["hci_transport"] = hci_transport
+    context.obj["trace"] = trace
+    context.obj["channel"] = channel
+    context.obj["uuid"] = uuid
+
+
+# -----------------------------------------------------------------------------
+@cli.command()
+@click.pass_context
+@click.option("--tcp-host", help="TCP host", default="localhost")
+@click.option("--tcp-port", help="TCP port", default=DEFAULT_SERVER_TCP_PORT)
+def server(context, tcp_host, tcp_port):
+    bridge = ServerBridge(
+        context.obj["channel"],
+        context.obj["uuid"],
+        context.obj["trace"],
+        tcp_host,
+        tcp_port,
+    )
+    asyncio.run(run(context.obj["device_config"], context.obj["hci_transport"], bridge))
+
+
+# -----------------------------------------------------------------------------
+@cli.command()
+@click.pass_context
+@click.argument("bluetooth-address")
+@click.option("--tcp-host", help="TCP host", default="_")
+@click.option("--tcp-port", help="TCP port", default=DEFAULT_CLIENT_TCP_PORT)
+@click.option("--encrypt", is_flag=True, help="Encrypt the connection")
+def client(context, bluetooth_address, tcp_host, tcp_port, encrypt):
+    bridge = ClientBridge(
+        context.obj["channel"],
+        context.obj["uuid"],
+        context.obj["trace"],
+        bluetooth_address,
+        tcp_host,
+        tcp_port,
+        encrypt,
+    )
+    asyncio.run(run(context.obj["device_config"], context.obj["hci_transport"], bridge))
+
+
+# -----------------------------------------------------------------------------
+logging.basicConfig(level=os.environ.get("BUMBLE_LOGLEVEL", "WARNING").upper())
+if __name__ == "__main__":
+    cli(obj={})  # pylint: disable=no-value-for-parameter
diff --git a/apps/speaker/speaker.py b/apps/speaker/speaker.py
index 84e05a0..fc2230a 100644
--- a/apps/speaker/speaker.py
+++ b/apps/speaker/speaker.py
@@ -76,6 +76,7 @@ logger = logging.getLogger(__name__)
 # -----------------------------------------------------------------------------
 DEFAULT_UI_PORT = 7654
 
+
 # -----------------------------------------------------------------------------
 class AudioExtractor:
     @staticmethod
diff --git a/apps/unbond.py b/apps/unbond.py
index 5ffd746..01cb9e5 100644
--- a/apps/unbond.py
+++ b/apps/unbond.py
@@ -24,6 +24,7 @@ from bumble.device import Device
 from bumble.keys import JsonKeyStore
 from bumble.transport import open_transport
 
+
 # -----------------------------------------------------------------------------
 async def unbond_with_keystore(keystore, address):
     if address is None:
diff --git a/bumble/a2dp.py b/bumble/a2dp.py
index 653a042..cac14e9 100644
--- a/bumble/a2dp.py
+++ b/bumble/a2dp.py
@@ -652,7 +652,9 @@ class SbcPacketSource:
 
                     # Prepare for next packets
                     sequence_number += 1
+                    sequence_number &= 0xFFFF
                     timestamp += sum((frame.sample_count for frame in frames))
+                    timestamp &= 0xFFFFFFFF
                     frames = [frame]
                     frames_size = len(frame.payload)
                 else:
diff --git a/bumble/att.py b/bumble/att.py
index 2bec4ea..0fce3ce 100644
--- a/bumble/att.py
+++ b/bumble/att.py
@@ -655,7 +655,7 @@ class ATT_Write_Command(ATT_PDU):
 @ATT_PDU.subclass(
     [
         ('attribute_handle', HANDLE_FIELD_SPEC),
-        ('attribute_value', '*')
+        ('attribute_value', '*'),
         # ('authentication_signature', 'TODO')
     ]
 )
diff --git a/bumble/avdtp.py b/bumble/avdtp.py
index f785109..713f7b7 100644
--- a/bumble/avdtp.py
+++ b/bumble/avdtp.py
@@ -325,8 +325,8 @@ class MediaPacket:
         self.padding = padding
         self.extension = extension
         self.marker = marker
-        self.sequence_number = sequence_number
-        self.timestamp = timestamp
+        self.sequence_number = sequence_number & 0xFFFF
+        self.timestamp = timestamp & 0xFFFFFFFF
         self.ssrc = ssrc
         self.csrc_list = csrc_list
         self.payload_type = payload_type
@@ -341,7 +341,12 @@ class MediaPacket:
                 | len(self.csrc_list),
                 self.marker << 7 | self.payload_type,
             ]
-        ) + struct.pack('>HII', self.sequence_number, self.timestamp, self.ssrc)
+        ) + struct.pack(
+            '>HII',
+            self.sequence_number,
+            self.timestamp,
+            self.ssrc,
+        )
         for csrc in self.csrc_list:
             header += struct.pack('>I', csrc)
         return header + self.payload
@@ -1545,9 +1550,10 @@ class Protocol(EventEmitter):
 
         assert False  # Should never reach this
 
-    async def get_capabilities(
-        self, seid: int
-    ) -> Union[Get_Capabilities_Response, Get_All_Capabilities_Response,]:
+    async def get_capabilities(self, seid: int) -> Union[
+        Get_Capabilities_Response,
+        Get_All_Capabilities_Response,
+    ]:
         if self.version > (1, 2):
             return await self.send_command(Get_All_Capabilities_Command(seid))
 
diff --git a/bumble/avrcp.py b/bumble/avrcp.py
index fec2b2c..11f4eff 100644
--- a/bumble/avrcp.py
+++ b/bumble/avrcp.py
@@ -1745,9 +1745,11 @@ class Protocol(pyee.EventEmitter):
                 avc.CommandFrame.CommandType.CONTROL,
                 avc.Frame.SubunitType.PANEL,
                 0,
-                avc.PassThroughFrame.StateFlag.PRESSED
-                if pressed
-                else avc.PassThroughFrame.StateFlag.RELEASED,
+                (
+                    avc.PassThroughFrame.StateFlag.PRESSED
+                    if pressed
+                    else avc.PassThroughFrame.StateFlag.RELEASED
+                ),
                 key,
                 b'',
             )
diff --git a/bumble/controller.py b/bumble/controller.py
index eb20292..f4cbe95 100644
--- a/bumble/controller.py
+++ b/bumble/controller.py
@@ -134,15 +134,15 @@ class Controller:
         self.hci_sink = None
         self.link = link
 
-        self.central_connections: Dict[
-            Address, Connection
-        ] = {}  # Connections where this controller is the central
-        self.peripheral_connections: Dict[
-            Address, Connection
-        ] = {}  # Connections where this controller is the peripheral
-        self.classic_connections: Dict[
-            Address, Connection
-        ] = {}  # Connections in BR/EDR
+        self.central_connections: Dict[Address, Connection] = (
+            {}
+        )  # Connections where this controller is the central
+        self.peripheral_connections: Dict[Address, Connection] = (
+            {}
+        )  # Connections where this controller is the peripheral
+        self.classic_connections: Dict[Address, Connection] = (
+            {}
+        )  # Connections in BR/EDR
         self.central_cis_links: Dict[int, CisLink] = {}  # CIS links by handle
         self.peripheral_cis_links: Dict[int, CisLink] = {}  # CIS links by handle
 
diff --git a/bumble/device.py b/bumble/device.py
index 48f9d58..f9e6b9d 100644
--- a/bumble/device.py
+++ b/bumble/device.py
@@ -17,12 +17,19 @@
 # -----------------------------------------------------------------------------
 from __future__ import annotations
 from enum import IntEnum
+import copy
 import functools
 import json
 import asyncio
 import logging
 import secrets
-from contextlib import asynccontextmanager, AsyncExitStack, closing
+import sys
+from contextlib import (
+    asynccontextmanager,
+    AsyncExitStack,
+    closing,
+    AbstractAsyncContextManager,
+)
 from dataclasses import dataclass, field
 from collections.abc import Iterable
 from typing import (
@@ -40,6 +47,7 @@ from typing import (
     overload,
     TYPE_CHECKING,
 )
+from typing_extensions import Self
 
 from pyee import EventEmitter
 
@@ -276,12 +284,12 @@ class Advertisement:
     data_bytes: bytes = b''
 
     # Constants
-    TX_POWER_NOT_AVAILABLE: ClassVar[
-        int
-    ] = HCI_LE_Extended_Advertising_Report_Event.TX_POWER_INFORMATION_NOT_AVAILABLE
-    RSSI_NOT_AVAILABLE: ClassVar[
-        int
-    ] = HCI_LE_Extended_Advertising_Report_Event.RSSI_NOT_AVAILABLE
+    TX_POWER_NOT_AVAILABLE: ClassVar[int] = (
+        HCI_LE_Extended_Advertising_Report_Event.TX_POWER_INFORMATION_NOT_AVAILABLE
+    )
+    RSSI_NOT_AVAILABLE: ClassVar[int] = (
+        HCI_LE_Extended_Advertising_Report_Event.RSSI_NOT_AVAILABLE
+    )
 
     def __post_init__(self) -> None:
         self.data = AdvertisingData.from_bytes(self.data_bytes)
@@ -558,7 +566,9 @@ class AdvertisingParameters:
     )
     primary_advertising_interval_min: int = DEVICE_DEFAULT_ADVERTISING_INTERVAL
     primary_advertising_interval_max: int = DEVICE_DEFAULT_ADVERTISING_INTERVAL
-    primary_advertising_channel_map: HCI_LE_Set_Extended_Advertising_Parameters_Command.ChannelMap = (
+    primary_advertising_channel_map: (
+        HCI_LE_Set_Extended_Advertising_Parameters_Command.ChannelMap
+    ) = (
         AdvertisingChannelMap.CHANNEL_37
         | AdvertisingChannelMap.CHANNEL_38
         | AdvertisingChannelMap.CHANNEL_39
@@ -957,8 +967,9 @@ class ScoLink(CompositeEventEmitter):
     acl_connection: Connection
     handle: int
     link_type: int
+    sink: Optional[Callable[[HCI_SynchronousDataPacket], Any]] = None
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         super().__init__()
 
     async def disconnect(
@@ -980,8 +991,9 @@ class CisLink(CompositeEventEmitter):
     cis_id: int  # CIS ID assigned by Central device
     cig_id: int  # CIG ID assigned by Central device
     state: State = State.PENDING
+    sink: Optional[Callable[[HCI_IsoDataPacket], Any]] = None
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         super().__init__()
 
     async def disconnect(
@@ -1138,14 +1150,12 @@ class Connection(CompositeEventEmitter):
     @overload
     async def create_l2cap_channel(
         self, spec: l2cap.ClassicChannelSpec
-    ) -> l2cap.ClassicChannel:
-        ...
+    ) -> l2cap.ClassicChannel: ...
 
     @overload
     async def create_l2cap_channel(
         self, spec: l2cap.LeCreditBasedChannelSpec
-    ) -> l2cap.LeCreditBasedChannel:
-        ...
+    ) -> l2cap.LeCreditBasedChannel: ...
 
     async def create_l2cap_channel(
         self, spec: Union[l2cap.ClassicChannelSpec, l2cap.LeCreditBasedChannelSpec]
@@ -1252,75 +1262,47 @@ class Connection(CompositeEventEmitter):
 
 
 # -----------------------------------------------------------------------------
+@dataclass
 class DeviceConfiguration:
-    def __init__(self) -> None:
-        # Setup defaults
-        self.name = DEVICE_DEFAULT_NAME
-        self.address = Address(DEVICE_DEFAULT_ADDRESS)
-        self.class_of_device = DEVICE_DEFAULT_CLASS_OF_DEVICE
-        self.scan_response_data = DEVICE_DEFAULT_SCAN_RESPONSE_DATA
-        self.advertising_interval_min = DEVICE_DEFAULT_ADVERTISING_INTERVAL
-        self.advertising_interval_max = DEVICE_DEFAULT_ADVERTISING_INTERVAL
-        self.le_enabled = True
-        # LE host enable 2nd parameter
-        self.le_simultaneous_enabled = False
-        self.classic_enabled = False
-        self.classic_sc_enabled = True
-        self.classic_ssp_enabled = True
-        self.classic_smp_enabled = True
-        self.classic_accept_any = True
-        self.connectable = True
-        self.discoverable = True
-        self.advertising_data = bytes(
-            AdvertisingData(
-                [(AdvertisingData.COMPLETE_LOCAL_NAME, bytes(self.name, 'utf-8'))]
-            )
+    # Setup defaults
+    name: str = DEVICE_DEFAULT_NAME
+    address: Address = Address(DEVICE_DEFAULT_ADDRESS)
+    class_of_device: int = DEVICE_DEFAULT_CLASS_OF_DEVICE
+    scan_response_data: bytes = DEVICE_DEFAULT_SCAN_RESPONSE_DATA
+    advertising_interval_min: int = DEVICE_DEFAULT_ADVERTISING_INTERVAL
+    advertising_interval_max: int = DEVICE_DEFAULT_ADVERTISING_INTERVAL
+    le_enabled: bool = True
+    # LE host enable 2nd parameter
+    le_simultaneous_enabled: bool = False
+    classic_enabled: bool = False
+    classic_sc_enabled: bool = True
+    classic_ssp_enabled: bool = True
+    classic_smp_enabled: bool = True
+    classic_accept_any: bool = True
+    connectable: bool = True
+    discoverable: bool = True
+    advertising_data: bytes = bytes(
+        AdvertisingData(
+            [(AdvertisingData.COMPLETE_LOCAL_NAME, bytes(DEVICE_DEFAULT_NAME, 'utf-8'))]
         )
-        self.irk = bytes(16)  # This really must be changed for any level of security
-        self.keystore = None
+    )
+    irk: bytes = bytes(16)  # This really must be changed for any level of security
+    keystore: Optional[str] = None
+    address_resolution_offload: bool = False
+    cis_enabled: bool = False
+
+    def __post_init__(self) -> None:
         self.gatt_services: List[Dict[str, Any]] = []
-        self.address_resolution_offload = False
-        self.cis_enabled = False
 
     def load_from_dict(self, config: Dict[str, Any]) -> None:
+        config = copy.deepcopy(config)
+
         # Load simple properties
-        self.name = config.get('name', self.name)
-        if address := config.get('address', None):
+        if address := config.pop('address', None):
             self.address = Address(address)
-        self.class_of_device = config.get('class_of_device', self.class_of_device)
-        self.advertising_interval_min = config.get(
-            'advertising_interval', self.advertising_interval_min
-        )
-        self.advertising_interval_max = self.advertising_interval_min
-        self.keystore = config.get('keystore')
-        self.le_enabled = config.get('le_enabled', self.le_enabled)
-        self.le_simultaneous_enabled = config.get(
-            'le_simultaneous_enabled', self.le_simultaneous_enabled
-        )
-        self.classic_enabled = config.get('classic_enabled', self.classic_enabled)
-        self.classic_sc_enabled = config.get(
-            'classic_sc_enabled', self.classic_sc_enabled
-        )
-        self.classic_ssp_enabled = config.get(
-            'classic_ssp_enabled', self.classic_ssp_enabled
-        )
-        self.classic_smp_enabled = config.get(
-            'classic_smp_enabled', self.classic_smp_enabled
-        )
-        self.classic_accept_any = config.get(
-            'classic_accept_any', self.classic_accept_any
-        )
-        self.connectable = config.get('connectable', self.connectable)
-        self.discoverable = config.get('discoverable', self.discoverable)
-        self.gatt_services = config.get('gatt_services', self.gatt_services)
-        self.address_resolution_offload = config.get(
-            'address_resolution_offload', self.address_resolution_offload
-        )
-        self.cis_enabled = config.get('cis_enabled', self.cis_enabled)
 
         # Load or synthesize an IRK
-        irk = config.get('irk')
-        if irk:
+        if irk := config.pop('irk', None):
             self.irk = bytes.fromhex(irk)
         elif self.address != Address(DEVICE_DEFAULT_ADDRESS):
             # Construct an IRK from the address bytes
@@ -1332,21 +1314,53 @@ class DeviceConfiguration:
             # Fallback - when both IRK and address are not set, randomly generate an IRK.
             self.irk = secrets.token_bytes(16)
 
+        if (name := config.pop('name', None)) is not None:
+            self.name = name
+
         # Load advertising data
-        advertising_data = config.get('advertising_data')
-        if advertising_data:
+        if advertising_data := config.pop('advertising_data', None):
             self.advertising_data = bytes.fromhex(advertising_data)
-        elif config.get('name') is not None:
+        elif name is not None:
             self.advertising_data = bytes(
                 AdvertisingData(
                     [(AdvertisingData.COMPLETE_LOCAL_NAME, bytes(self.name, 'utf-8'))]
                 )
             )
 
-    def load_from_file(self, filename):
+        # Load advertising interval (for backward compatibility)
+        if advertising_interval := config.pop('advertising_interval', None):
+            self.advertising_interval_min = advertising_interval
+            self.advertising_interval_max = advertising_interval
+            if (
+                'advertising_interval_max' in config
+                or 'advertising_interval_min' in config
+            ):
+                logger.warning(
+                    'Trying to set both advertising_interval and '
+                    'advertising_interval_min/max, advertising_interval will be'
+                    'ignored.'
+                )
+
+        # Load data in primitive types.
+        for key, value in config.items():
+            setattr(self, key, value)
+
+    def load_from_file(self, filename: str) -> None:
         with open(filename, 'r', encoding='utf-8') as file:
             self.load_from_dict(json.load(file))
 
+    @classmethod
+    def from_file(cls: Type[Self], filename: str) -> Self:
+        config = cls()
+        config.load_from_file(filename)
+        return config
+
+    @classmethod
+    def from_dict(cls: Type[Self], config: Dict[str, Any]) -> Self:
+        device_config = cls()
+        device_config.load_from_dict(config)
+        return device_config
+
 
 # -----------------------------------------------------------------------------
 # Decorators used with the following Device class
@@ -1470,8 +1484,7 @@ class Device(CompositeEventEmitter):
 
     @classmethod
     def from_config_file(cls, filename: str) -> Device:
-        config = DeviceConfiguration()
-        config.load_from_file(filename)
+        config = DeviceConfiguration.from_file(filename)
         return cls(config=config)
 
     @classmethod
@@ -1488,8 +1501,7 @@ class Device(CompositeEventEmitter):
     def from_config_file_with_hci(
         cls, filename: str, hci_source: TransportSource, hci_sink: TransportSink
     ) -> Device:
-        config = DeviceConfiguration()
-        config.load_from_file(filename)
+        config = DeviceConfiguration.from_file(filename)
         return cls.from_config_with_hci(config, hci_source, hci_sink)
 
     def __init__(
@@ -1529,6 +1541,12 @@ class Device(CompositeEventEmitter):
             Address.ANY: []
         }  # Futures, by BD address OR [Futures] for Address.ANY
 
+        # In Python <= 3.9 + Rust Runtime, asyncio.Lock cannot be properly initiated.
+        if sys.version_info >= (3, 10):
+            self._cis_lock = asyncio.Lock()
+        else:
+            self._cis_lock = AsyncExitStack()
+
         # Own address type cache
         self.connect_own_address_type = None
 
@@ -1723,16 +1741,14 @@ class Device(CompositeEventEmitter):
         self,
         connection: Connection,
         spec: l2cap.ClassicChannelSpec,
-    ) -> l2cap.ClassicChannel:
-        ...
+    ) -> l2cap.ClassicChannel: ...
 
     @overload
     async def create_l2cap_channel(
         self,
         connection: Connection,
         spec: l2cap.LeCreditBasedChannelSpec,
-    ) -> l2cap.LeCreditBasedChannel:
-        ...
+    ) -> l2cap.LeCreditBasedChannel: ...
 
     async def create_l2cap_channel(
         self,
@@ -1753,16 +1769,14 @@ class Device(CompositeEventEmitter):
         self,
         spec: l2cap.ClassicChannelSpec,
         handler: Optional[Callable[[l2cap.ClassicChannel], Any]] = None,
-    ) -> l2cap.ClassicChannelServer:
-        ...
+    ) -> l2cap.ClassicChannelServer: ...
 
     @overload
     def create_l2cap_server(
         self,
         spec: l2cap.LeCreditBasedChannelSpec,
         handler: Optional[Callable[[l2cap.LeCreditBasedChannel], Any]] = None,
-    ) -> l2cap.LeCreditBasedChannelServer:
-        ...
+    ) -> l2cap.LeCreditBasedChannelServer: ...
 
     def create_l2cap_server(
         self,
@@ -2188,7 +2202,7 @@ class Device(CompositeEventEmitter):
             # controller.
             await self.send_command(
                 HCI_LE_Remove_Advertising_Set_Command(
-                    advertising_handle=advertising_data
+                    advertising_handle=advertising_handle
                 ),
                 check_result=False,
             )
@@ -3289,17 +3303,19 @@ class Device(CompositeEventEmitter):
 
         handler = self.on(
             'remote_name',
-            lambda address, remote_name: pending_name.set_result(remote_name)
-            if address == peer_address
-            else None,
+            lambda address, remote_name: (
+                pending_name.set_result(remote_name)
+                if address == peer_address
+                else None
+            ),
         )
         failure_handler = self.on(
             'remote_name_failure',
-            lambda address, error_code: pending_name.set_exception(
-                HCI_Error(error_code)
-            )
-            if address == peer_address
-            else None,
+            lambda address, error_code: (
+                pending_name.set_exception(HCI_Error(error_code))
+                if address == peer_address
+                else None
+            ),
         )
 
         try:
@@ -3404,49 +3420,71 @@ class Device(CompositeEventEmitter):
                 for cis_handle, _ in cis_acl_pairs
             }
 
-            @watcher.on(self, 'cis_establishment')
             def on_cis_establishment(cis_link: CisLink) -> None:
                 if pending_future := pending_cis_establishments.get(cis_link.handle):
                     pending_future.set_result(cis_link)
 
-            result = await self.send_command(
+            def on_cis_establishment_failure(cis_handle: int, status: int) -> None:
+                if pending_future := pending_cis_establishments.get(cis_handle):
+                    pending_future.set_exception(HCI_Error(status))
+
+            watcher.on(self, 'cis_establishment', on_cis_establishment)
+            watcher.on(self, 'cis_establishment_failure', on_cis_establishment_failure)
+            await self.send_command(
                 HCI_LE_Create_CIS_Command(
                     cis_connection_handle=[p[0] for p in cis_acl_pairs],
                     acl_connection_handle=[p[1] for p in cis_acl_pairs],
                 ),
+                check_result=True,
             )
-            if result.status != HCI_COMMAND_STATUS_PENDING:
-                logger.warning(
-                    'HCI_LE_Create_CIS_Command failed: '
-                    f'{HCI_Constant.error_name(result.status)}'
-                )
-                raise HCI_StatusError(result)
 
             return await asyncio.gather(*pending_cis_establishments.values())
 
     # [LE only]
     @experimental('Only for testing.')
     async def accept_cis_request(self, handle: int) -> CisLink:
-        result = await self.send_command(
-            HCI_LE_Accept_CIS_Request_Command(connection_handle=handle),
-        )
-        if result.status != HCI_COMMAND_STATUS_PENDING:
-            logger.warning(
-                'HCI_LE_Accept_CIS_Request_Command failed: '
-                f'{HCI_Constant.error_name(result.status)}'
-            )
-            raise HCI_StatusError(result)
+        """[LE Only] Accepts an incoming CIS request.
 
-        pending_cis_establishment = asyncio.get_running_loop().create_future()
+        When the specified CIS handle is already created, this method returns the
+        existed CIS link object immediately.
 
-        with closing(EventWatcher()) as watcher:
+        Args:
+            handle: CIS handle to accept.
 
-            @watcher.on(self, 'cis_establishment')
-            def on_cis_establishment(cis_link: CisLink) -> None:
-                if cis_link.handle == handle:
-                    pending_cis_establishment.set_result(cis_link)
+        Returns:
+            CIS link object on the given handle.
+        """
+        if not (cis_link := self.cis_links.get(handle)):
+            raise InvalidStateError(f'No pending CIS request of handle {handle}')
+
+        # There might be multiple ASE sharing a CIS channel.
+        # If one of them has accepted the request, the others should just leverage it.
+        async with self._cis_lock:
+            if cis_link.state == CisLink.State.ESTABLISHED:
+                return cis_link
+
+            with closing(EventWatcher()) as watcher:
+                pending_establishment = asyncio.get_running_loop().create_future()
+
+                def on_establishment() -> None:
+                    pending_establishment.set_result(None)
+
+                def on_establishment_failure(status: int) -> None:
+                    pending_establishment.set_exception(HCI_Error(status))
+
+                watcher.on(cis_link, 'establishment', on_establishment)
+                watcher.on(cis_link, 'establishment_failure', on_establishment_failure)
+
+                await self.send_command(
+                    HCI_LE_Accept_CIS_Request_Command(connection_handle=handle),
+                    check_result=True,
+                )
+
+                await pending_establishment
+                return cis_link
 
-            return await pending_cis_establishment
+        # Mypy believes this is reachable when context is an ExitStack.
+        raise InvalidStateError('Unreachable')
 
     # [LE only]
     @experimental('Only for testing.')
@@ -3455,15 +3493,10 @@ class Device(CompositeEventEmitter):
         handle: int,
         reason: int = HCI_REMOTE_USER_TERMINATED_CONNECTION_ERROR,
     ) -> None:
-        result = await self.send_command(
+        await self.send_command(
             HCI_LE_Reject_CIS_Request_Command(connection_handle=handle, reason=reason),
+            check_result=True,
         )
-        if result.status != HCI_COMMAND_STATUS_PENDING:
-            logger.warning(
-                'HCI_LE_Reject_CIS_Request_Command failed: '
-                f'{HCI_Constant.error_name(result.status)}'
-            )
-            raise HCI_StatusError(result)
 
     async def get_remote_le_features(self, connection: Connection) -> LeFeatureMask:
         """[LE Only] Reads remote LE supported features.
@@ -3475,19 +3508,25 @@ class Device(CompositeEventEmitter):
             LE features supported by the remote device.
         """
         with closing(EventWatcher()) as watcher:
-            read_feature_future: asyncio.Future[
-                LeFeatureMask
-            ] = asyncio.get_running_loop().create_future()
+            read_feature_future: asyncio.Future[LeFeatureMask] = (
+                asyncio.get_running_loop().create_future()
+            )
 
             def on_le_remote_features(handle: int, features: int):
                 if handle == connection.handle:
                     read_feature_future.set_result(LeFeatureMask(features))
 
+            def on_failure(handle: int, status: int):
+                if handle == connection.handle:
+                    read_feature_future.set_exception(HCI_Error(status))
+
             watcher.on(self.host, 'le_remote_features', on_le_remote_features)
+            watcher.on(self.host, 'le_remote_features_failure', on_failure)
             await self.send_command(
                 HCI_LE_Read_Remote_Features_Command(
                     connection_handle=connection.handle
                 ),
+                check_result=True,
             )
             return await read_feature_future
 
@@ -3662,7 +3701,6 @@ class Device(CompositeEventEmitter):
                 # We were connected via a legacy advertisement.
                 if self.legacy_advertiser:
                     own_address_type = self.legacy_advertiser.own_address_type
-                    self.legacy_advertiser = None
                 else:
                     # This should not happen, but just in case, pick a default.
                     logger.warning("connection without an advertiser")
@@ -3693,15 +3731,14 @@ class Device(CompositeEventEmitter):
         )
         self.connections[connection_handle] = connection
 
-        if (
-            role == HCI_PERIPHERAL_ROLE
-            and self.legacy_advertiser
-            and self.legacy_advertiser.auto_restart
-        ):
-            connection.once(
-                'disconnection',
-                lambda _: self.abort_on('flush', self.legacy_advertiser.start()),
-            )
+        if role == HCI_PERIPHERAL_ROLE and self.legacy_advertiser:
+            if self.legacy_advertiser.auto_restart:
+                connection.once(
+                    'disconnection',
+                    lambda _: self.abort_on('flush', self.legacy_advertiser.start()),
+                )
+            else:
+                self.legacy_advertiser = None
 
         if role == HCI_CENTRAL_ROLE or not self.supports_le_extended_advertising:
             # We can emit now, we have all the info we need
@@ -4109,8 +4146,8 @@ class Device(CompositeEventEmitter):
     @host_event_handler
     @experimental('Only for testing')
     def on_sco_packet(self, sco_handle: int, packet: HCI_SynchronousDataPacket) -> None:
-        if sco_link := self.sco_links.get(sco_handle):
-            sco_link.emit('pdu', packet)
+        if (sco_link := self.sco_links.get(sco_handle)) and sco_link.sink:
+            sco_link.sink(packet)
 
     # [LE only]
     @host_event_handler
@@ -4166,15 +4203,15 @@ class Device(CompositeEventEmitter):
     def on_cis_establishment_failure(self, cis_handle: int, status: int) -> None:
         logger.debug(f'*** CIS Establishment Failure: cis=[0x{cis_handle:04X}] ***')
         if cis_link := self.cis_links.pop(cis_handle):
-            cis_link.emit('establishment_failure')
+            cis_link.emit('establishment_failure', status)
         self.emit('cis_establishment_failure', cis_handle, status)
 
     # [LE only]
     @host_event_handler
     @experimental('Only for testing')
     def on_iso_packet(self, handle: int, packet: HCI_IsoDataPacket) -> None:
-        if cis_link := self.cis_links.get(handle):
-            cis_link.emit('pdu', packet)
+        if (cis_link := self.cis_links.get(handle)) and cis_link.sink:
+            cis_link.sink(packet)
 
     @host_event_handler
     @with_connection_from_handle
diff --git a/bumble/gap.py b/bumble/gap.py
index 29df89f..c07a30d 100644
--- a/bumble/gap.py
+++ b/bumble/gap.py
@@ -36,6 +36,7 @@ logger = logging.getLogger(__name__)
 # Classes
 # -----------------------------------------------------------------------------
 
+
 # -----------------------------------------------------------------------------
 class GenericAccessService(Service):
     def __init__(self, device_name, appearance=(0, 0)):
diff --git a/bumble/gatt.py b/bumble/gatt.py
index 71c01f4..896cec0 100644
--- a/bumble/gatt.py
+++ b/bumble/gatt.py
@@ -342,9 +342,11 @@ class Service(Attribute):
             uuid = UUID(uuid)
 
         super().__init__(
-            GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE
-            if primary
-            else GATT_SECONDARY_SERVICE_ATTRIBUTE_TYPE,
+            (
+                GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE
+                if primary
+                else GATT_SECONDARY_SERVICE_ATTRIBUTE_TYPE
+            ),
             Attribute.READABLE,
             uuid.to_pdu_bytes(),
         )
@@ -560,9 +562,9 @@ class CharacteristicAdapter:
 
     def __init__(self, characteristic: Union[Characteristic, AttributeProxy]):
         self.wrapped_characteristic = characteristic
-        self.subscribers: Dict[
-            Callable, Callable
-        ] = {}  # Map from subscriber to proxy subscriber
+        self.subscribers: Dict[Callable, Callable] = (
+            {}
+        )  # Map from subscriber to proxy subscriber
 
         if isinstance(characteristic, Characteristic):
             self.read_value = self.read_encoded_value
diff --git a/bumble/gatt_client.py b/bumble/gatt_client.py
index 2079a65..c71aabd 100644
--- a/bumble/gatt_client.py
+++ b/bumble/gatt_client.py
@@ -91,6 +91,22 @@ logger = logging.getLogger(__name__)
 
 
 # -----------------------------------------------------------------------------
+# Utils
+# -----------------------------------------------------------------------------
+
+
+def show_services(services: Iterable[ServiceProxy]) -> None:
+    for service in services:
+        print(color(str(service), 'cyan'))
+
+        for characteristic in service.characteristics:
+            print(color('  ' + str(characteristic), 'magenta'))
+
+            for descriptor in characteristic.descriptors:
+                print(color('    ' + str(descriptor), 'green'))
+
+
+# -----------------------------------------------------------------------------
 # Proxies
 # -----------------------------------------------------------------------------
 class AttributeProxy(EventEmitter):
@@ -352,9 +368,7 @@ class Client:
             if c.uuid == uuid
         ]
 
-    def get_attribute_grouping(
-        self, attribute_handle: int
-    ) -> Optional[
+    def get_attribute_grouping(self, attribute_handle: int) -> Optional[
         Union[
             ServiceProxy,
             Tuple[ServiceProxy, CharacteristicProxy],
diff --git a/bumble/gatt_server.py b/bumble/gatt_server.py
index 3be4185..be2b88e 100644
--- a/bumble/gatt_server.py
+++ b/bumble/gatt_server.py
@@ -445,9 +445,9 @@ class Server(EventEmitter):
             assert self.pending_confirmations[connection.handle] is None
 
             # Create a future value to hold the eventual response
-            pending_confirmation = self.pending_confirmations[
-                connection.handle
-            ] = asyncio.get_running_loop().create_future()
+            pending_confirmation = self.pending_confirmations[connection.handle] = (
+                asyncio.get_running_loop().create_future()
+            )
 
             try:
                 self.send_gatt_pdu(connection.handle, indication.to_bytes())
diff --git a/bumble/hci.py b/bumble/hci.py
index 013a2d3..9ef40bf 100644
--- a/bumble/hci.py
+++ b/bumble/hci.py
@@ -23,7 +23,7 @@ import functools
 import logging
 import secrets
 import struct
-from typing import Any, Callable, Dict, Iterable, List, Optional, Type, Union
+from typing import Any, Callable, Dict, Iterable, List, Optional, Type, Union, ClassVar
 
 from bumble import crypto
 from .colors import color
@@ -2003,7 +2003,7 @@ class HCI_Packet:
     Abstract Base class for HCI packets
     '''
 
-    hci_packet_type: int
+    hci_packet_type: ClassVar[int]
 
     @staticmethod
     def from_bytes(packet: bytes) -> HCI_Packet:
@@ -4249,9 +4249,11 @@ class HCI_LE_Set_Extended_Scan_Parameters_Command(HCI_Command):
             fields.append(
                 (
                     f'{scanning_phy_str}.scan_type:    ',
-                    'PASSIVE'
-                    if self.scan_types[i] == self.PASSIVE_SCANNING
-                    else 'ACTIVE',
+                    (
+                        'PASSIVE'
+                        if self.scan_types[i] == self.PASSIVE_SCANNING
+                        else 'ACTIVE'
+                    ),
                 )
             )
             fields.append(
@@ -5010,9 +5012,9 @@ class HCI_LE_Advertising_Report_Event(HCI_LE_Meta_Event):
         return f'{color(self.subevent_name(self.subevent_code), "magenta")}:\n{reports}'
 
 
-HCI_LE_Meta_Event.subevent_classes[
-    HCI_LE_ADVERTISING_REPORT_EVENT
-] = HCI_LE_Advertising_Report_Event
+HCI_LE_Meta_Event.subevent_classes[HCI_LE_ADVERTISING_REPORT_EVENT] = (
+    HCI_LE_Advertising_Report_Event
+)
 
 
 # -----------------------------------------------------------------------------
@@ -5264,9 +5266,9 @@ class HCI_LE_Extended_Advertising_Report_Event(HCI_LE_Meta_Event):
         return f'{color(self.subevent_name(self.subevent_code), "magenta")}:\n{reports}'
 
 
-HCI_LE_Meta_Event.subevent_classes[
-    HCI_LE_EXTENDED_ADVERTISING_REPORT_EVENT
-] = HCI_LE_Extended_Advertising_Report_Event
+HCI_LE_Meta_Event.subevent_classes[HCI_LE_EXTENDED_ADVERTISING_REPORT_EVENT] = (
+    HCI_LE_Extended_Advertising_Report_Event
+)
 
 
 # -----------------------------------------------------------------------------
@@ -6190,12 +6192,23 @@ class HCI_SynchronousDataPacket(HCI_Packet):
 
 
 # -----------------------------------------------------------------------------
+@dataclasses.dataclass
 class HCI_IsoDataPacket(HCI_Packet):
     '''
     See Bluetooth spec @ 5.4.5 HCI ISO Data Packets
     '''
 
-    hci_packet_type = HCI_ISO_DATA_PACKET
+    hci_packet_type: ClassVar[int] = HCI_ISO_DATA_PACKET
+
+    connection_handle: int
+    data_total_length: int
+    iso_sdu_fragment: bytes
+    pb_flag: int
+    ts_flag: int = 0
+    time_stamp: Optional[int] = None
+    packet_sequence_number: Optional[int] = None
+    iso_sdu_length: Optional[int] = None
+    packet_status_flag: Optional[int] = None
 
     @staticmethod
     def from_bytes(packet: bytes) -> HCI_IsoDataPacket:
@@ -6239,28 +6252,6 @@ class HCI_IsoDataPacket(HCI_Packet):
             iso_sdu_fragment=iso_sdu_fragment,
         )
 
-    def __init__(
-        self,
-        connection_handle: int,
-        pb_flag: int,
-        ts_flag: int,
-        data_total_length: int,
-        time_stamp: Optional[int],
-        packet_sequence_number: Optional[int],
-        iso_sdu_length: Optional[int],
-        packet_status_flag: Optional[int],
-        iso_sdu_fragment: bytes,
-    ) -> None:
-        self.connection_handle = connection_handle
-        self.pb_flag = pb_flag
-        self.ts_flag = ts_flag
-        self.data_total_length = data_total_length
-        self.time_stamp = time_stamp
-        self.packet_sequence_number = packet_sequence_number
-        self.iso_sdu_length = iso_sdu_length
-        self.packet_status_flag = packet_status_flag
-        self.iso_sdu_fragment = iso_sdu_fragment
-
     def __bytes__(self) -> bytes:
         return self.to_bytes()
 
diff --git a/bumble/hfp.py b/bumble/hfp.py
index 27bb097..69dab26 100644
--- a/bumble/hfp.py
+++ b/bumble/hfp.py
@@ -15,6 +15,9 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
+
+import collections
 import collections.abc
 import logging
 import asyncio
@@ -22,15 +25,32 @@ import dataclasses
 import enum
 import traceback
 import pyee
-from typing import Dict, List, Union, Set, Any, Optional, TYPE_CHECKING
+import re
+from typing import (
+    Dict,
+    List,
+    Union,
+    Set,
+    Any,
+    Optional,
+    Type,
+    Tuple,
+    ClassVar,
+    Iterable,
+    TYPE_CHECKING,
+)
+from typing_extensions import Self
 
 from bumble import at
+from bumble import device
 from bumble import rfcomm
+from bumble import sdp
 from bumble.colors import color
 from bumble.core import (
     ProtocolError,
     BT_GENERIC_AUDIO_SERVICE,
     BT_HANDSFREE_SERVICE,
+    BT_HANDSFREE_AUDIO_GATEWAY_SERVICE,
     BT_L2CAP_PROTOCOL_ID,
     BT_RFCOMM_PROTOCOL_ID,
 )
@@ -39,15 +59,6 @@ from bumble.hci import (
     CodingFormat,
     CodecID,
 )
-from bumble.sdp import (
-    DataElement,
-    ServiceAttribute,
-    SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID,
-    SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
-    SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-    SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-    SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
-)
 
 
 # -----------------------------------------------------------------------------
@@ -193,17 +204,22 @@ class HfIndicator(enum.IntEnum):
     BATTERY_LEVEL = 0x02  # Battery level feature
 
 
-class CallHoldOperation(enum.IntEnum):
+class CallHoldOperation(enum.Enum):
     """
     Call Hold supported operations (normative).
 
     AT Commands Reference Guide, 3.5.2.3.12 +CHLD - Call Holding Services.
     """
 
-    RELEASE_ALL_HELD_CALLS = 0  # Release all held calls
-    RELEASE_ALL_ACTIVE_CALLS = 1  # Release all active calls, accept other
-    HOLD_ALL_ACTIVE_CALLS = 2  # Place all active calls on hold, accept other
-    ADD_HELD_CALL = 3  # Adds a held call to conversation
+    RELEASE_ALL_HELD_CALLS = "0"  # Release all held calls
+    RELEASE_ALL_ACTIVE_CALLS = "1"  # Release all active calls, accept other
+    RELEASE_SPECIFIC_CALL = "1x"  # Release a specific call X
+    HOLD_ALL_ACTIVE_CALLS = "2"  # Place all active calls on hold, accept other
+    HOLD_ALL_CALLS_EXCEPT = "2x"  # Place all active calls except call X
+    ADD_HELD_CALL = "3"  # Adds a held call to conversation
+    CONNECT_TWO_CALLS = (
+        "4"  # Connects the two calls and disconnects the subscriber from both calls
+    )
 
 
 class ResponseHoldStatus(enum.IntEnum):
@@ -324,16 +340,103 @@ class CallInfo:
     status: CallInfoStatus
     mode: CallInfoMode
     multi_party: CallInfoMultiParty
-    number: Optional[int] = None
+    number: Optional[str] = None
     type: Optional[int] = None
 
 
+@dataclasses.dataclass
+class CallLineIdentification:
+    """
+    Calling Line Identification notification.
+
+    TS 127 007 - V6.8.0, 7.6 Calling line identification presentation +CLIP, but only
+    number, type and alpha are meaningful in HFP.
+
+    Attributes:
+        number: String type phone number of format specified by `type`.
+        type: Type of address octet in integer format (refer TS 24.008 [8] subclause
+        10.5.4.7).
+        subaddr: String type subaddress of format specified by `satype`.
+        satype: Type of subaddress octet in integer format (refer TS 24.008 [8]
+        subclause 10.5.4.8).
+        alpha: Optional string type alphanumeric representation of number corresponding
+        to the entry found in phonebook; used character set should be the one selected
+        with command Select TE Character Set +CSCS.
+        cli_validity: 0 CLI valid, 1 CLI has been withheld by the originator, 2 CLI is
+        not available due to interworking problems or limitations of originating
+        network.
+    """
+
+    number: str
+    type: int
+    subaddr: Optional[str] = None
+    satype: Optional[int] = None
+    alpha: Optional[str] = None
+    cli_validity: Optional[int] = None
+
+    @classmethod
+    def parse_from(cls: Type[Self], parameters: List[bytes]) -> Self:
+        return cls(
+            number=parameters[0].decode(),
+            type=int(parameters[1]),
+            subaddr=parameters[2].decode() if len(parameters) >= 3 else None,
+            satype=(
+                int(parameters[3]) if len(parameters) >= 4 and parameters[3] else None
+            ),
+            alpha=parameters[4].decode() if len(parameters) >= 5 else None,
+            cli_validity=(
+                int(parameters[5]) if len(parameters) >= 6 and parameters[5] else None
+            ),
+        )
+
+    def to_clip_string(self) -> str:
+        return ','.join(
+            str(arg) if arg else ''
+            for arg in [
+                self.number,
+                self.type,
+                self.subaddr,
+                self.satype,
+                self.alpha,
+                self.cli_validity,
+            ]
+        )
+
+
+class VoiceRecognitionState(enum.IntEnum):
+    """
+    vrec values provided in AT+BVRA command.
+
+    Hands-Free Profile v1.8, 4.34.2, AT Capabilities Re-Used from GSM 07.07 and 3GPP 27.007.
+    """
+
+    DISABLE = 0
+    ENABLE = 1
+    # (Enhanced Voice Recognition Status only) HF is ready to accept audio.
+    ENHANCED_READY = 2
+
+
+class CmeError(enum.IntEnum):
+    """
+    CME ERROR codes (partial listed).
+
+    TS 127 007 - V6.8.0, 9.2.1 General errors
+    """
+
+    PHONE_FAILURE = 0
+    OPERATION_NOT_ALLOWED = 3
+    OPERATION_NOT_SUPPORTED = 4
+    MEMORY_FULL = 20
+    INVALID_INDEX = 21
+    NOT_FOUND = 22
+
+
 # -----------------------------------------------------------------------------
 # Hands-Free Control Interoperability Requirements
 # -----------------------------------------------------------------------------
 
 # Response codes.
-RESPONSE_CODES = [
+RESPONSE_CODES = {
     "+APLSIRI",
     "+BAC",
     "+BCC",
@@ -364,10 +467,10 @@ RESPONSE_CODES = [
     "+XAPL",
     "A",
     "D",
-]
+}
 
 # Unsolicited responses and statuses.
-UNSOLICITED_CODES = [
+UNSOLICITED_CODES = {
     "+APLSIRI",
     "+BCS",
     "+BIND",
@@ -385,10 +488,10 @@ UNSOLICITED_CODES = [
     "NO ANSWER",
     "NO CARRIER",
     "RING",
-]
+}
 
 # Status codes
-STATUS_CODES = [
+STATUS_CODES = {
     "+CME ERROR",
     "BLACKLISTED",
     "BUSY",
@@ -397,16 +500,25 @@ STATUS_CODES = [
     "NO ANSWER",
     "NO CARRIER",
     "OK",
-]
+}
 
 
 @dataclasses.dataclass
-class Configuration:
+class HfConfiguration:
     supported_hf_features: List[HfFeature]
     supported_hf_indicators: List[HfIndicator]
     supported_audio_codecs: List[AudioCodec]
 
 
+@dataclasses.dataclass
+class AgConfiguration:
+    supported_ag_features: Iterable[AgFeature]
+    supported_ag_indicators: collections.abc.Sequence[AgIndicatorState]
+    supported_hf_indicators: Iterable[HfIndicator]
+    supported_ag_call_hold_operations: Iterable[CallHoldOperation]
+    supported_audio_codecs: Iterable[AudioCodec]
+
+
 class AtResponseType(enum.Enum):
     """
     Indicates if a response is expected from an AT command, and if multiple responses are accepted.
@@ -417,31 +529,165 @@ class AtResponseType(enum.Enum):
     MULTIPLE = 2
 
 
+@dataclasses.dataclass
 class AtResponse:
     code: str
     parameters: list
 
-    def __init__(self, response: bytearray):
-        code_and_parameters = response.split(b':')
+    @classmethod
+    def parse_from(cls: Type[Self], buffer: bytearray) -> Self:
+        code_and_parameters = buffer.split(b':')
         parameters = (
             code_and_parameters[1] if len(code_and_parameters) > 1 else bytearray()
         )
-        self.code = code_and_parameters[0].decode()
-        self.parameters = at.parse_parameters(parameters)
+        return cls(
+            code=code_and_parameters[0].decode(),
+            parameters=at.parse_parameters(parameters),
+        )
+
+
+@dataclasses.dataclass
+class AtCommand:
+    class SubCode(str, enum.Enum):
+        NONE = ''
+        SET = '='
+        TEST = '=?'
+        READ = '?'
+
+    code: str
+    sub_code: SubCode
+    parameters: list
+
+    _PARSE_PATTERN: ClassVar[re.Pattern] = re.compile(
+        r'AT\+(?P<code>[A-Z]+)(?P<sub_code>=\?|=|\?)?(?P<parameters>.*)'
+    )
+
+    @classmethod
+    def parse_from(cls: Type[Self], buffer: bytearray) -> Self:
+        if not (match := cls._PARSE_PATTERN.fullmatch(buffer.decode())):
+            if buffer.startswith(b'ATA'):
+                return cls(code='A', sub_code=AtCommand.SubCode.NONE, parameters=[])
+            if buffer.startswith(b'ATD'):
+                return cls(
+                    code='D', sub_code=AtCommand.SubCode.NONE, parameters=[buffer[3:]]
+                )
+            raise HfpProtocolError('Invalid command')
+
+        parameters = []
+        if parameters_text := match.group('parameters'):
+            parameters = at.parse_parameters(parameters_text.encode())
+
+        return cls(
+            code=match.group('code'),
+            sub_code=AtCommand.SubCode(match.group('sub_code') or ''),
+            parameters=parameters,
+        )
 
 
 @dataclasses.dataclass
 class AgIndicatorState:
-    description: str
-    index: int
+    """State wrapper of AG indicator.
+
+    Attributes:
+        indicator: Indicator of this indicator state.
+        supported_values: Supported values of this indicator.
+        current_status: Current status of this indicator.
+        index: (HF only) Index of this indicator.
+        enabled: (AG only) Whether this indicator is enabled to report.
+        on_test_text: Text message reported in AT+CIND=? of this indicator.
+    """
+
+    indicator: AgIndicator
     supported_values: Set[int]
     current_status: int
+    index: Optional[int] = None
+    enabled: bool = True
+
+    @property
+    def on_test_text(self) -> str:
+        min_value = min(self.supported_values)
+        max_value = max(self.supported_values)
+        if len(self.supported_values) == (max_value - min_value + 1):
+            supported_values_text = f'({min_value}-{max_value})'
+        else:
+            supported_values_text = (
+                f'({",".join(str(v) for v in self.supported_values)})'
+            )
+        return f'(\"{self.indicator.value}\",{supported_values_text})'
+
+    @classmethod
+    def call(cls: Type[Self]) -> Self:
+        """Default call indicator state."""
+        return cls(
+            indicator=AgIndicator.CALL, supported_values={0, 1}, current_status=0
+        )
+
+    @classmethod
+    def callsetup(cls: Type[Self]) -> Self:
+        """Default callsetup indicator state."""
+        return cls(
+            indicator=AgIndicator.CALL_SETUP,
+            supported_values={0, 1, 2, 3},
+            current_status=0,
+        )
+
+    @classmethod
+    def callheld(cls: Type[Self]) -> Self:
+        """Default call indicator state."""
+        return cls(
+            indicator=AgIndicator.CALL_HELD,
+            supported_values={0, 1, 2},
+            current_status=0,
+        )
+
+    @classmethod
+    def service(cls: Type[Self]) -> Self:
+        """Default service indicator state."""
+        return cls(
+            indicator=AgIndicator.SERVICE, supported_values={0, 1}, current_status=0
+        )
+
+    @classmethod
+    def signal(cls: Type[Self]) -> Self:
+        """Default signal indicator state."""
+        return cls(
+            indicator=AgIndicator.SIGNAL,
+            supported_values={0, 1, 2, 3, 4, 5},
+            current_status=0,
+        )
+
+    @classmethod
+    def roam(cls: Type[Self]) -> Self:
+        """Default roam indicator state."""
+        return cls(
+            indicator=AgIndicator.CALL, supported_values={0, 1}, current_status=0
+        )
+
+    @classmethod
+    def battchg(cls: Type[Self]) -> Self:
+        """Default battery charge indicator state."""
+        return cls(
+            indicator=AgIndicator.BATTERY_CHARGE,
+            supported_values={0, 1, 2, 3, 4, 5},
+            current_status=0,
+        )
 
 
 @dataclasses.dataclass
 class HfIndicatorState:
+    """State wrapper of HF indicator.
+
+    Attributes:
+        indicator: Indicator of this indicator state.
+        supported: Whether this indicator is supported.
+        enabled: Whether this indicator is enabled.
+        current_status: Current (last-reported) status value of this indicaotr.
+    """
+
+    indicator: HfIndicator
     supported: bool = False
     enabled: bool = False
+    current_status: int = 0
 
 
 class HfProtocol(pyee.EventEmitter):
@@ -457,8 +703,26 @@ class HfProtocol(pyee.EventEmitter):
         ag_indicator: When AG update their indicators, notify the new state.
             Args:
                 ag_indicator: AgIndicator
+        speaker_volume: Emitted when AG update speaker volume autonomously.
+            Args:
+                volume: Int
+        microphone_volume: Emitted when AG update microphone volume autonomously.
+            Args:
+                volume: Int
+        microphone_volume: Emitted when AG sends a ringtone request.
+            Args:
+                None
+        cli_notification: Emitted when notify the call metadata on line.
+            Args:
+                cli_notification: CallLineIdentification
+        voice_recognition: Emitted when AG starts voice recognition autonomously.
+            Args:
+                vrec: VoiceRecognitionState
     """
 
+    class HfLoopTermination(HfpProtocolError):
+        """Termination signal for run() loop."""
+
     supported_hf_features: int
     supported_audio_codecs: List[AudioCodec]
 
@@ -472,14 +736,18 @@ class HfProtocol(pyee.EventEmitter):
     command_lock: asyncio.Lock
     if TYPE_CHECKING:
         response_queue: asyncio.Queue[AtResponse]
-        unsolicited_queue: asyncio.Queue[AtResponse]
+        unsolicited_queue: asyncio.Queue[Optional[AtResponse]]
     else:
         response_queue: asyncio.Queue
         unsolicited_queue: asyncio.Queue
     read_buffer: bytearray
     active_codec: AudioCodec
 
-    def __init__(self, dlc: rfcomm.DLC, configuration: Configuration) -> None:
+    def __init__(
+        self,
+        dlc: rfcomm.DLC,
+        configuration: HfConfiguration,
+    ) -> None:
         super().__init__()
 
         # Configure internal state.
@@ -489,13 +757,14 @@ class HfProtocol(pyee.EventEmitter):
         self.unsolicited_queue = asyncio.Queue()
         self.read_buffer = bytearray()
         self.active_codec = AudioCodec.CVSD
+        self._slc_initialized = False
 
         # Build local features.
         self.supported_hf_features = sum(configuration.supported_hf_features)
         self.supported_audio_codecs = configuration.supported_audio_codecs
 
         self.hf_indicators = {
-            indicator: HfIndicatorState()
+            indicator: HfIndicatorState(indicator=indicator)
             for indicator in configuration.supported_hf_indicators
         }
 
@@ -506,6 +775,10 @@ class HfProtocol(pyee.EventEmitter):
 
         # Bind the AT reader to the RFCOMM channel.
         self.dlc.sink = self._read_at
+        # Stop the run() loop when L2CAP is closed.
+        self.dlc.multiplexer.l2cap_channel.on(
+            'close', lambda: self.unsolicited_queue.put_nowait(None)
+        )
 
     def supports_hf_feature(self, feature: HfFeature) -> bool:
         return (self.supported_hf_features & feature) != 0
@@ -530,7 +803,7 @@ class HfProtocol(pyee.EventEmitter):
 
         # Isolate the AT response code and parameters.
         raw_response = self.read_buffer[header + 2 : trailer]
-        response = AtResponse(raw_response)
+        response = AtResponse.parse_from(raw_response)
         logger.debug(f"<<< {raw_response.decode()}")
 
         # Consume the response bytes.
@@ -616,7 +889,7 @@ class HfProtocol(pyee.EventEmitter):
             # If both the HF and AG do support the Codec Negotiation feature
             # then the HF shall send the AT+BAC=<HF available codecs> command to
             # the AG to notify the AG of the available codecs in the HF.
-            codecs = [str(c) for c in self.supported_audio_codecs]
+            codecs = [str(c.value) for c in self.supported_audio_codecs]
             await self.execute_command(f"AT+BAC={','.join(codecs)}")
 
         # 4.2.1.3 AG Indicators
@@ -634,7 +907,7 @@ class HfProtocol(pyee.EventEmitter):
 
         self.ag_indicators = []
         for index, indicator in enumerate(response.parameters):
-            description = indicator[0].decode()
+            description = AgIndicator(indicator[0].decode())
             supported_values = []
             for value in indicator[1]:
                 value = value.split(b'-')
@@ -664,7 +937,7 @@ class HfProtocol(pyee.EventEmitter):
 
         if self.supports_hf_feature(
             HfFeature.THREE_WAY_CALLING
-        ) and self.supports_ag_feature(HfFeature.THREE_WAY_CALLING):
+        ) and self.supports_ag_feature(AgFeature.THREE_WAY_CALLING):
             # After the HF has enabled the “Indicators status update” function in
             # the AG, and if the “Call waiting and 3-way calling” bit was set in the
             # supported features bitmap by both the HF and the AG, the HF shall
@@ -677,9 +950,8 @@ class HfProtocol(pyee.EventEmitter):
             )
 
             self.supported_ag_call_hold_operations = [
-                CallHoldOperation(int(operation))
+                CallHoldOperation(operation.decode())
                 for operation in response.parameters[0]
-                if not b'x' in operation
             ]
 
         # 4.2.1.4 HF Indicators
@@ -692,7 +964,7 @@ class HfProtocol(pyee.EventEmitter):
             # shall send the AT+BIND=<HF supported HF indicators> command to the AG
             # to notify the AG of the supported indicators’ assigned numbers in the
             # HF. The AG shall respond with OK
-            indicators = [str(i) for i in self.hf_indicators.keys()]
+            indicators = [str(i.value) for i in self.hf_indicators]
             await self.execute_command(f"AT+BIND={','.join(indicators)}")
 
             # After having provided the AG with the HF indicators it supports,
@@ -728,6 +1000,7 @@ class HfProtocol(pyee.EventEmitter):
                     self.hf_indicators[indicator].enabled = True
 
         logger.info("SLC setup completed")
+        self._slc_initialized = True
 
     async def setup_audio_connection(self):
         """4.11.2 Audio Connection Setup by HF."""
@@ -808,28 +1081,46 @@ class HfProtocol(pyee.EventEmitter):
                 mode=CallInfoMode(int(response.parameters[3])),
                 multi_party=CallInfoMultiParty(int(response.parameters[4])),
             )
+            if len(response.parameters) >= 6:
+                call_info.number = response.parameters[5].decode()
             if len(response.parameters) >= 7:
-                call_info.number = int(response.parameters[5])
                 call_info.type = int(response.parameters[6])
             calls.append(call_info)
         return calls
 
     async def update_ag_indicator(self, index: int, value: int):
-        self.ag_indicators[index].current_status = value
-        self.emit('ag_indicator', self.ag_indicators[index])
-        logger.info(
-            f"AG indicator updated: {self.ag_indicators[index].description}, {value}"
-        )
+        # CIEV is in 1-index, while ag_indicators is in 0-index.
+        ag_indicator = self.ag_indicators[index - 1]
+        ag_indicator.current_status = value
+        self.emit('ag_indicator', ag_indicator)
+        logger.info(f"AG indicator updated: {ag_indicator.indicator}, {value}")
 
     async def handle_unsolicited(self):
         """Handle unsolicited result codes sent by the audio gateway."""
         result = await self.unsolicited_queue.get()
+        if not result:
+            raise HfProtocol.HfLoopTermination()
         if result.code == "+BCS":
             await self.setup_codec_connection(int(result.parameters[0]))
         elif result.code == "+CIEV":
             await self.update_ag_indicator(
                 int(result.parameters[0]), int(result.parameters[1])
             )
+        elif result.code == "+VGS":
+            self.emit('speaker_volume', int(result.parameters[0]))
+        elif result.code == "+VGM":
+            self.emit('microphone_volume', int(result.parameters[0]))
+        elif result.code == "RING":
+            self.emit('ring')
+        elif result.code == "+CLIP":
+            self.emit(
+                'cli_notification', CallLineIdentification.parse_from(result.parameters)
+            )
+        elif result.code == "+BVRA":
+            # TODO: Support Enhanced Voice Recognition.
+            self.emit(
+                'voice_recognition', VoiceRecognitionState(int(result.parameters[0]))
+            )
         else:
             logging.info(f"unhandled unsolicited response {result.code}")
 
@@ -841,14 +1132,479 @@ class HfProtocol(pyee.EventEmitter):
         """
 
         try:
-            await self.initiate_slc()
+            if not self._slc_initialized:
+                await self.initiate_slc()
             while True:
                 await self.handle_unsolicited()
+        except HfProtocol.HfLoopTermination:
+            logger.info('Loop terminated')
         except Exception:
             logger.error("HFP-HF protocol failed with the following error:")
             logger.error(traceback.format_exc())
 
 
+class AgProtocol(pyee.EventEmitter):
+    """
+    Implementation for the Audio-Gateway side of the Hands-Free profile.
+
+    Reference specification Hands-Free Profile v1.8.
+
+    Emitted events:
+        slc_complete: Emit when SLC procedure is completed.
+        codec_negotiation: When codec is renegotiated, notify the new codec.
+            Args:
+                active_codec: AudioCodec
+        hf_indicator: When HF update their indicators, notify the new state.
+            Args:
+                hf_indicator: HfIndicatorState
+        codec_connection_request: Emit when HF sends AT+BCC to request codec connection.
+        answer: Emit when HF sends ATA to answer phone call.
+        hang_up: Emit when HF sends AT+CHUP to hang up phone call.
+        dial: Emit when HF sends ATD to dial phone call.
+        voice_recognition: Emit when HF requests voice recognition state.
+            Args:
+                vrec: VoiceRecognitionState
+        call_hold: Emit when HF requests call hold operation.
+            Args:
+                operation: CallHoldOperation
+                call_index: Optional[int]
+        speaker_volume: Emitted when AG update speaker volume autonomously.
+            Args:
+                volume: Int
+        microphone_volume: Emitted when AG update microphone volume autonomously.
+            Args:
+                volume: Int
+    """
+
+    supported_hf_features: int
+    supported_hf_indicators: Set[HfIndicator]
+    supported_audio_codecs: List[AudioCodec]
+
+    supported_ag_features: int
+    supported_ag_call_hold_operations: List[CallHoldOperation]
+
+    ag_indicators: List[AgIndicatorState]
+    hf_indicators: collections.OrderedDict[HfIndicator, HfIndicatorState]
+
+    dlc: rfcomm.DLC
+
+    read_buffer: bytearray
+    active_codec: AudioCodec
+    calls: List[CallInfo]
+
+    indicator_report_enabled: bool
+    inband_ringtone_enabled: bool
+    cme_error_enabled: bool
+    cli_notification_enabled: bool
+    call_waiting_enabled: bool
+    _remained_slc_setup_features: Set[HfFeature]
+
+    def __init__(self, dlc: rfcomm.DLC, configuration: AgConfiguration) -> None:
+        super().__init__()
+
+        # Configure internal state.
+        self.dlc = dlc
+        self.read_buffer = bytearray()
+        self.active_codec = AudioCodec.CVSD
+        self.calls = []
+
+        # Build local features.
+        self.supported_ag_features = sum(configuration.supported_ag_features)
+        self.supported_ag_call_hold_operations = list(
+            configuration.supported_ag_call_hold_operations
+        )
+        self.ag_indicators = list(configuration.supported_ag_indicators)
+        self.supported_hf_indicators = set(configuration.supported_hf_indicators)
+        self.inband_ringtone_enabled = True
+        self._remained_slc_setup_features = set()
+
+        # Clear remote features.
+        self.supported_hf_features = 0
+        self.supported_audio_codecs = []
+        self.indicator_report_enabled = False
+        self.cme_error_enabled = False
+        self.cli_notification_enabled = False
+        self.call_waiting_enabled = False
+
+        self.hf_indicators = collections.OrderedDict()
+
+        # Bind the AT reader to the RFCOMM channel.
+        self.dlc.sink = self._read_at
+
+    def supports_hf_feature(self, feature: HfFeature) -> bool:
+        return (self.supported_hf_features & feature) != 0
+
+    def supports_ag_feature(self, feature: AgFeature) -> bool:
+        return (self.supported_ag_features & feature) != 0
+
+    def _read_at(self, data: bytes):
+        """
+        Reads AT messages from the RFCOMM channel.
+        """
+        # Append to the read buffer.
+        self.read_buffer.extend(data)
+
+        # Locate the trailer.
+        trailer = self.read_buffer.find(b'\r')
+        if trailer == -1:
+            return
+
+        # Isolate the AT response code and parameters.
+        raw_command = self.read_buffer[:trailer]
+        command = AtCommand.parse_from(raw_command)
+        logger.debug(f"<<< {raw_command.decode()}")
+
+        # Consume the response bytes.
+        self.read_buffer = self.read_buffer[trailer + 1 :]
+
+        if command.sub_code == AtCommand.SubCode.TEST:
+            handler_name = f'_on_{command.code.lower()}_test'
+        elif command.sub_code == AtCommand.SubCode.READ:
+            handler_name = f'_on_{command.code.lower()}_read'
+        else:
+            handler_name = f'_on_{command.code.lower()}'
+
+        if handler := getattr(self, handler_name, None):
+            handler(*command.parameters)
+        else:
+            logger.warning('Handler %s not found', handler_name)
+            self.send_response('ERROR')
+
+    def send_response(self, response: str) -> None:
+        """Sends an AT response."""
+        self.dlc.write(f'\r\n{response}\r\n')
+
+    def send_cme_error(self, error_code: CmeError) -> None:
+        """Sends an CME ERROR response.
+
+        If CME Error is not enabled by HF, sends ERROR instead.
+        """
+        if self.cme_error_enabled:
+            self.send_response(f'+CME ERROR: {error_code.value}')
+        else:
+            self.send_error()
+
+    def send_ok(self) -> None:
+        """Sends an OK response."""
+        self.send_response('OK')
+
+    def send_error(self) -> None:
+        """Sends an ERROR response."""
+        self.send_response('ERROR')
+
+    def set_inband_ringtone_enabled(self, enabled: bool) -> None:
+        """Enables or disables in-band ringtone."""
+
+        self.inband_ringtone_enabled = enabled
+        self.send_response(f'+BSIR: {1 if enabled else 0}')
+
+    def set_speaker_volume(self, level: int) -> None:
+        """Reports speaker volume."""
+
+        self.send_response(f'+VGS: {level}')
+
+    def set_microphone_volume(self, level: int) -> None:
+        """Reports microphone volume."""
+
+        self.send_response(f'+VGM: {level}')
+
+    def send_ring(self) -> None:
+        """Sends RING command to trigger ringtone on HF."""
+
+        self.send_response('RING')
+
+    def update_ag_indicator(self, indicator: AgIndicator, value: int) -> None:
+        """Updates AG indicator.
+
+        Args:
+            indicator: Name of the indicator.
+            value: new value of the indicator.
+        """
+
+        search_result = next(
+            (
+                (index, state)
+                for index, state in enumerate(self.ag_indicators)
+                if state.indicator == indicator
+            ),
+            None,
+        )
+        if not search_result:
+            raise KeyError(f'{indicator} is not supported.')
+
+        index, indicator_state = search_result
+        if not self.indicator_report_enabled:
+            logger.warning('AG indicator report is disabled')
+        if not indicator_state.enabled:
+            logger.warning(f'AG indicator {indicator} is disabled')
+
+        indicator_state.current_status = value
+        self.send_response(f'+CIEV: {index+1},{value}')
+
+    async def negotiate_codec(self, codec: AudioCodec) -> None:
+        """Starts codec negotiation."""
+
+        if not self.supports_ag_feature(AgFeature.CODEC_NEGOTIATION):
+            logger.warning('Local does not support Codec Negotiation')
+        if not self.supports_hf_feature(HfFeature.CODEC_NEGOTIATION):
+            logger.warning('Peer does not support Codec Negotiation')
+        if codec not in self.supported_audio_codecs:
+            logger.warning(f'{codec} is not supported by peer')
+
+        at_bcs_future = asyncio.get_running_loop().create_future()
+        self.once('codec_negotiation', at_bcs_future.set_result)
+        self.send_response(f'+BCS: {codec.value}')
+        if (new_codec := await at_bcs_future) != codec:
+            raise HfpProtocolError(f'Expect codec: {codec}, but get {new_codec}')
+
+    def send_cli_notification(self, cli: CallLineIdentification) -> None:
+        """Sends +CLIP CLI notification."""
+
+        if not self.cli_notification_enabled:
+            logger.warning('Try to send CLIP while CLI notification is not enabled')
+
+        self.send_response(f'+CLIP: {cli.to_clip_string()}')
+
+    def _check_remained_slc_commands(self) -> None:
+        if not self._remained_slc_setup_features:
+            self.emit('slc_complete')
+
+    def _on_brsf(self, hf_features: bytes) -> None:
+        self.supported_hf_features = int(hf_features)
+        self.send_response(f'+BRSF: {self.supported_ag_features}')
+        self.send_ok()
+
+        if self.supports_hf_feature(
+            HfFeature.HF_INDICATORS
+        ) and self.supports_ag_feature(AgFeature.HF_INDICATORS):
+            self._remained_slc_setup_features.add(HfFeature.HF_INDICATORS)
+
+        if self.supports_hf_feature(
+            HfFeature.THREE_WAY_CALLING
+        ) and self.supports_ag_feature(AgFeature.THREE_WAY_CALLING):
+            self._remained_slc_setup_features.add(HfFeature.THREE_WAY_CALLING)
+
+    def _on_bac(self, *args) -> None:
+        self.supported_audio_codecs = [AudioCodec(int(value)) for value in args]
+        self.send_ok()
+
+    def _on_bcs(self, codec: bytes) -> None:
+        self.active_codec = AudioCodec(int(codec))
+        self.send_ok()
+        self.emit('codec_negotiation', self.active_codec)
+
+    def _on_bvra(self, vrec: bytes) -> None:
+        self.send_ok()
+        self.emit('voice_recognition', VoiceRecognitionState(int(vrec)))
+
+    def _on_chld(self, operation_code: bytes) -> None:
+        call_index: Optional[int] = None
+        if len(operation_code) > 1:
+            call_index = int(operation_code[1:])
+            operation_code = operation_code[:1] + b'x'
+        try:
+            operation = CallHoldOperation(operation_code.decode())
+        except:
+            logger.error(f'Invalid operation: {operation_code.decode()}')
+            self.send_cme_error(CmeError.OPERATION_NOT_SUPPORTED)
+            return
+
+        if operation not in self.supported_ag_call_hold_operations:
+            logger.error(f'Unsupported operation: {operation_code.decode()}')
+            self.send_cme_error(CmeError.OPERATION_NOT_SUPPORTED)
+
+        if call_index is not None and not any(
+            call.index == call_index for call in self.calls
+        ):
+            logger.error(f'No matching call {call_index}')
+            self.send_cme_error(CmeError.INVALID_INDEX)
+
+        # Real three-way calls have more complicated situations, but this is not a popular issue - let users to handle the remaining :)
+
+        self.send_ok()
+        self.emit('call_hold', operation, call_index)
+
+    def _on_chld_test(self) -> None:
+        if not self.supports_ag_feature(AgFeature.THREE_WAY_CALLING):
+            self.send_error()
+            return
+
+        self.send_response(
+            '+CHLD: ({})'.format(
+                ','.join(
+                    operation.value
+                    for operation in self.supported_ag_call_hold_operations
+                )
+            )
+        )
+        self.send_ok()
+        self._remained_slc_setup_features.remove(HfFeature.THREE_WAY_CALLING)
+        self._check_remained_slc_commands()
+
+    def _on_cind_test(self) -> None:
+        if not self.ag_indicators:
+            self.send_cme_error(CmeError.NOT_FOUND)
+            return
+
+        indicator_list_str = ",".join(
+            indicator.on_test_text for indicator in self.ag_indicators
+        )
+        self.send_response(f'+CIND: {indicator_list_str}')
+        self.send_ok()
+
+    def _on_cind_read(self) -> None:
+        if not self.ag_indicators:
+            self.send_cme_error(CmeError.NOT_FOUND)
+            return
+
+        indicator_list_str = ",".join(
+            str(indicator.current_status) for indicator in self.ag_indicators
+        )
+        self.send_response(f'+CIND: {indicator_list_str}')
+        self.send_ok()
+
+        self._check_remained_slc_commands()
+
+    def _on_cmer(
+        self,
+        mode: bytes,
+        keypad: Optional[bytes] = None,
+        display: Optional[bytes] = None,
+        indicator: bytes = b'',
+    ) -> None:
+        if (
+            int(mode) != 3
+            or (keypad and int(keypad))
+            or (display and int(display))
+            or int(indicator) not in (0, 1)
+        ):
+            logger.error(
+                f'Unexpected values: mode={mode!r}, keypad={keypad!r}, '
+                f'display={display!r}, indicator={indicator!r}'
+            )
+            self.send_cme_error(CmeError.INVALID_INDEX)
+
+        self.indicator_report_enabled = bool(int(indicator))
+        self.send_ok()
+
+    def _on_cmee(self, enabled: bytes) -> None:
+        self.cme_error_enabled = bool(int(enabled))
+        self.send_ok()
+
+    def _on_ccwa(self, enabled: bytes) -> None:
+        self.call_waiting_enabled = bool(int(enabled))
+        self.send_ok()
+
+    def _on_bind(self, *args) -> None:
+        if not self.supports_ag_feature(AgFeature.HF_INDICATORS):
+            self.send_error()
+            return
+
+        peer_supported_indicators = set(
+            HfIndicator(int(indicator)) for indicator in args
+        )
+        self.hf_indicators = collections.OrderedDict(
+            {
+                indicator: HfIndicatorState(indicator=indicator)
+                for indicator in self.supported_hf_indicators.intersection(
+                    peer_supported_indicators
+                )
+            }
+        )
+        self.send_ok()
+
+    def _on_bind_test(self) -> None:
+        if not self.supports_ag_feature(AgFeature.HF_INDICATORS):
+            self.send_error()
+            return
+
+        hf_indicator_list_str = ",".join(
+            str(indicator.value) for indicator in self.supported_hf_indicators
+        )
+        self.send_response(f'+BIND: ({hf_indicator_list_str})')
+        self.send_ok()
+
+    def _on_bind_read(self) -> None:
+        if not self.supports_ag_feature(AgFeature.HF_INDICATORS):
+            self.send_error()
+            return
+
+        for indicator in self.hf_indicators:
+            self.send_response(f'+BIND: {indicator.value},1')
+
+        self.send_ok()
+
+        self._remained_slc_setup_features.remove(HfFeature.HF_INDICATORS)
+        self._check_remained_slc_commands()
+
+    def _on_biev(self, index_bytes: bytes, value_bytes: bytes) -> None:
+        if not self.supports_ag_feature(AgFeature.HF_INDICATORS):
+            self.send_error()
+            return
+
+        index = HfIndicator(int(index_bytes))
+        if index not in self.hf_indicators:
+            self.send_error()
+            return
+
+        self.hf_indicators[index].current_status = int(value_bytes)
+        self.emit('hf_indicator', self.hf_indicators[index])
+        self.send_ok()
+
+    def _on_bia(self, *args) -> None:
+        for enabled, state in zip(args, self.ag_indicators):
+            state.enabled = bool(int(enabled))
+        self.send_ok()
+
+    def _on_bcc(self) -> None:
+        self.emit('codec_connection_request')
+        self.send_ok()
+
+    def _on_a(self) -> None:
+        """ATA handler."""
+        self.emit('answer')
+        self.send_ok()
+
+    def _on_d(self, number: bytes) -> None:
+        """ATD handler."""
+        self.emit('dial', number.decode())
+        self.send_ok()
+
+    def _on_chup(self) -> None:
+        self.emit('hang_up')
+        self.send_ok()
+
+    def _on_clcc(self) -> None:
+        for call in self.calls:
+            number_text = f',\"{call.number}\"' if call.number is not None else ''
+            type_text = f',{call.type}' if call.type is not None else ''
+            response = (
+                f'+CLCC: {call.index}'
+                f',{call.direction.value}'
+                f',{call.status.value}'
+                f',{call.mode.value}'
+                f',{call.multi_party.value}'
+                f'{number_text}'
+                f'{type_text}'
+            )
+            self.send_response(response)
+        self.send_ok()
+
+    def _on_clip(self, enabled: bytes) -> None:
+        if not self.supports_hf_feature(HfFeature.CLI_PRESENTATION_CAPABILITY):
+            logger.error('Remote doesn not support CLI but sends AT+CLIP')
+        self.cli_notification_enabled = True if enabled == b'1' else False
+        self.send_ok()
+
+    def _on_vgs(self, level: bytes) -> None:
+        self.emit('speaker_volume', int(level))
+        self.send_ok()
+
+    def _on_vgm(self, level: bytes) -> None:
+        self.emit('microphone_volume', int(level))
+        self.send_ok()
+
+
 # -----------------------------------------------------------------------------
 # Normative SDP definitions
 # -----------------------------------------------------------------------------
@@ -902,9 +1658,12 @@ class AgSdpFeature(enum.IntFlag):
     VOICE_RECOGNITION_TEST = 0x80
 
 
-def sdp_records(
-    service_record_handle: int, rfcomm_channel: int, configuration: Configuration
-) -> List[ServiceAttribute]:
+def make_hf_sdp_records(
+    service_record_handle: int,
+    rfcomm_channel: int,
+    configuration: HfConfiguration,
+    version: ProfileVersion = ProfileVersion.V1_8,
+) -> List[sdp.ServiceAttribute]:
     """
     Generates the SDP record for HFP Hands-Free support.
 
@@ -936,53 +1695,234 @@ def sdp_records(
         hf_supported_features |= HfSdpFeature.WIDE_BAND
 
     return [
-        ServiceAttribute(
-            SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID,
-            DataElement.unsigned_integer_32(service_record_handle),
+        sdp.ServiceAttribute(
+            sdp.SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID,
+            sdp.DataElement.unsigned_integer_32(service_record_handle),
+        ),
+        sdp.ServiceAttribute(
+            sdp.SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
+                [
+                    sdp.DataElement.uuid(BT_HANDSFREE_SERVICE),
+                    sdp.DataElement.uuid(BT_GENERIC_AUDIO_SERVICE),
+                ]
+            ),
+        ),
+        sdp.ServiceAttribute(
+            sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
+                [
+                    sdp.DataElement.sequence(
+                        [sdp.DataElement.uuid(BT_L2CAP_PROTOCOL_ID)]
+                    ),
+                    sdp.DataElement.sequence(
+                        [
+                            sdp.DataElement.uuid(BT_RFCOMM_PROTOCOL_ID),
+                            sdp.DataElement.unsigned_integer_8(rfcomm_channel),
+                        ]
+                    ),
+                ]
+            ),
+        ),
+        sdp.ServiceAttribute(
+            sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
+                [
+                    sdp.DataElement.sequence(
+                        [
+                            sdp.DataElement.uuid(BT_HANDSFREE_SERVICE),
+                            sdp.DataElement.unsigned_integer_16(version),
+                        ]
+                    )
+                ]
+            ),
+        ),
+        sdp.ServiceAttribute(
+            sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
+            sdp.DataElement.unsigned_integer_16(hf_supported_features),
+        ),
+    ]
+
+
+def make_ag_sdp_records(
+    service_record_handle: int,
+    rfcomm_channel: int,
+    configuration: AgConfiguration,
+    version: ProfileVersion = ProfileVersion.V1_8,
+) -> List[sdp.ServiceAttribute]:
+    """
+    Generates the SDP record for HFP Audio-Gateway support.
+
+    The record exposes the features supported in the input configuration,
+    and the allocated RFCOMM channel.
+    """
+
+    ag_supported_features = 0
+
+    if AgFeature.EC_NR in configuration.supported_ag_features:
+        ag_supported_features |= AgSdpFeature.EC_NR
+    if AgFeature.THREE_WAY_CALLING in configuration.supported_ag_features:
+        ag_supported_features |= AgSdpFeature.THREE_WAY_CALLING
+    if (
+        AgFeature.ENHANCED_VOICE_RECOGNITION_STATUS
+        in configuration.supported_ag_features
+    ):
+        ag_supported_features |= AgSdpFeature.ENHANCED_VOICE_RECOGNITION_STATUS
+    if AgFeature.VOICE_RECOGNITION_TEST in configuration.supported_ag_features:
+        ag_supported_features |= AgSdpFeature.VOICE_RECOGNITION_TEST
+    if AgFeature.IN_BAND_RING_TONE_CAPABILITY in configuration.supported_ag_features:
+        ag_supported_features |= AgSdpFeature.IN_BAND_RING_TONE_CAPABILITY
+    if AgFeature.VOICE_RECOGNITION_FUNCTION in configuration.supported_ag_features:
+        ag_supported_features |= AgSdpFeature.VOICE_RECOGNITION_FUNCTION
+    if AudioCodec.MSBC in configuration.supported_audio_codecs:
+        ag_supported_features |= AgSdpFeature.WIDE_BAND
+
+    return [
+        sdp.ServiceAttribute(
+            sdp.SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID,
+            sdp.DataElement.unsigned_integer_32(service_record_handle),
         ),
-        ServiceAttribute(
-            SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
-            DataElement.sequence(
+        sdp.ServiceAttribute(
+            sdp.SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
                 [
-                    DataElement.uuid(BT_HANDSFREE_SERVICE),
-                    DataElement.uuid(BT_GENERIC_AUDIO_SERVICE),
+                    sdp.DataElement.uuid(BT_HANDSFREE_AUDIO_GATEWAY_SERVICE),
+                    sdp.DataElement.uuid(BT_GENERIC_AUDIO_SERVICE),
                 ]
             ),
         ),
-        ServiceAttribute(
-            SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-            DataElement.sequence(
+        sdp.ServiceAttribute(
+            sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
                 [
-                    DataElement.sequence([DataElement.uuid(BT_L2CAP_PROTOCOL_ID)]),
-                    DataElement.sequence(
+                    sdp.DataElement.sequence(
+                        [sdp.DataElement.uuid(BT_L2CAP_PROTOCOL_ID)]
+                    ),
+                    sdp.DataElement.sequence(
                         [
-                            DataElement.uuid(BT_RFCOMM_PROTOCOL_ID),
-                            DataElement.unsigned_integer_8(rfcomm_channel),
+                            sdp.DataElement.uuid(BT_RFCOMM_PROTOCOL_ID),
+                            sdp.DataElement.unsigned_integer_8(rfcomm_channel),
                         ]
                     ),
                 ]
             ),
         ),
-        ServiceAttribute(
-            SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-            DataElement.sequence(
+        sdp.ServiceAttribute(
+            sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+            sdp.DataElement.sequence(
                 [
-                    DataElement.sequence(
+                    sdp.DataElement.sequence(
                         [
-                            DataElement.uuid(BT_HANDSFREE_SERVICE),
-                            DataElement.unsigned_integer_16(ProfileVersion.V1_8),
+                            sdp.DataElement.uuid(BT_HANDSFREE_AUDIO_GATEWAY_SERVICE),
+                            sdp.DataElement.unsigned_integer_16(version),
                         ]
                     )
                 ]
             ),
         ),
-        ServiceAttribute(
-            SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
-            DataElement.unsigned_integer_16(hf_supported_features),
+        sdp.ServiceAttribute(
+            sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
+            sdp.DataElement.unsigned_integer_16(ag_supported_features),
         ),
     ]
 
 
+async def find_hf_sdp_record(
+    connection: device.Connection,
+) -> Optional[Tuple[int, ProfileVersion, HfSdpFeature]]:
+    """Searches a Hands-Free SDP record from remote device.
+
+    Args:
+        connection: ACL connection to make SDP search.
+
+    Returns:
+        Tuple of (<RFCOMM channel>, <Profile Version>, <HF SDP features>)
+    """
+    async with sdp.Client(connection) as sdp_client:
+        search_result = await sdp_client.search_attributes(
+            uuids=[BT_HANDSFREE_SERVICE],
+            attribute_ids=[
+                sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+                sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+                sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
+                sdp.SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
+            ],
+        )
+        for attribute_lists in search_result:
+            channel: Optional[int] = None
+            version: Optional[ProfileVersion] = None
+            features: Optional[HfSdpFeature] = None
+            for attribute in attribute_lists:
+                # The layout is [[L2CAP_PROTOCOL], [RFCOMM_PROTOCOL, RFCOMM_CHANNEL]].
+                if attribute.id == sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID:
+                    protocol_descriptor_list = attribute.value.value
+                    channel = protocol_descriptor_list[1].value[1].value
+                elif (
+                    attribute.id
+                    == sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID
+                ):
+                    profile_descriptor_list = attribute.value.value
+                    version = ProfileVersion(profile_descriptor_list[0].value[1].value)
+                elif attribute.id == sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID:
+                    features = HfSdpFeature(attribute.value.value)
+                elif attribute.id == sdp.SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID:
+                    class_id_list = attribute.value.value
+                    uuid = class_id_list[0].value
+                    # AG record may also contain HF UUID in its profile descriptor list.
+                    # If found, skip this record.
+                    if uuid == BT_HANDSFREE_AUDIO_GATEWAY_SERVICE:
+                        channel, version, features = (None, None, None)
+                        break
+
+            if channel is not None and version is not None and features is not None:
+                return (channel, version, features)
+    return None
+
+
+async def find_ag_sdp_record(
+    connection: device.Connection,
+) -> Optional[Tuple[int, ProfileVersion, AgSdpFeature]]:
+    """Searches an Audio-Gateway SDP record from remote device.
+
+    Args:
+        connection: ACL connection to make SDP search.
+
+    Returns:
+        Tuple of (<RFCOMM channel>, <Profile Version>, <AG SDP features>)
+    """
+    async with sdp.Client(connection) as sdp_client:
+        search_result = await sdp_client.search_attributes(
+            uuids=[BT_HANDSFREE_AUDIO_GATEWAY_SERVICE],
+            attribute_ids=[
+                sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+                sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
+                sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID,
+            ],
+        )
+        for attribute_lists in search_result:
+            channel: Optional[int] = None
+            version: Optional[ProfileVersion] = None
+            features: Optional[AgSdpFeature] = None
+            for attribute in attribute_lists:
+                # The layout is [[L2CAP_PROTOCOL], [RFCOMM_PROTOCOL, RFCOMM_CHANNEL]].
+                if attribute.id == sdp.SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID:
+                    protocol_descriptor_list = attribute.value.value
+                    channel = protocol_descriptor_list[1].value[1].value
+                elif (
+                    attribute.id
+                    == sdp.SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID
+                ):
+                    profile_descriptor_list = attribute.value.value
+                    version = ProfileVersion(profile_descriptor_list[0].value[1].value)
+                elif attribute.id == sdp.SDP_SUPPORTED_FEATURES_ATTRIBUTE_ID:
+                    features = AgSdpFeature(attribute.value.value)
+            if not channel or not version or features is None:
+                logger.warning(f"Bad result {attribute_lists}.")
+                return None
+            return (channel, version, features)
+    return None
+
+
 # -----------------------------------------------------------------------------
 # ESCO Codec Default Parameters
 # -----------------------------------------------------------------------------
@@ -1006,7 +1946,9 @@ class EscoParameters:
     transmit_coding_format: CodingFormat
     receive_coding_format: CodingFormat
     packet_type: HCI_Enhanced_Setup_Synchronous_Connection_Command.PacketType
-    retransmission_effort: HCI_Enhanced_Setup_Synchronous_Connection_Command.RetransmissionEffort
+    retransmission_effort: (
+        HCI_Enhanced_Setup_Synchronous_Connection_Command.RetransmissionEffort
+    )
     max_latency: int
 
     # Common
@@ -1014,12 +1956,12 @@ class EscoParameters:
     output_coding_format: CodingFormat = CodingFormat(CodecID.LINEAR_PCM)
     input_coded_data_size: int = 16
     output_coded_data_size: int = 16
-    input_pcm_data_format: HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat = (
-        HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat.TWOS_COMPLEMENT
-    )
-    output_pcm_data_format: HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat = (
-        HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat.TWOS_COMPLEMENT
-    )
+    input_pcm_data_format: (
+        HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat
+    ) = HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat.TWOS_COMPLEMENT
+    output_pcm_data_format: (
+        HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat
+    ) = HCI_Enhanced_Setup_Synchronous_Connection_Command.PcmDataFormat.TWOS_COMPLEMENT
     input_pcm_sample_payload_msb_position: int = 0
     output_pcm_sample_payload_msb_position: int = 0
     input_data_path: HCI_Enhanced_Setup_Synchronous_Connection_Command.DataPath = (
diff --git a/bumble/hid.py b/bumble/hid.py
index fc5c807..1b4aa00 100644
--- a/bumble/hid.py
+++ b/bumble/hid.py
@@ -48,6 +48,7 @@ HID_INTERRUPT_PSM = 0x0013
 
 class Message:
     message_type: MessageType
+
     # Report types
     class ReportType(enum.IntEnum):
         OTHER_REPORT = 0x00
diff --git a/bumble/host.py b/bumble/host.py
index fd0a247..64b6668 100644
--- a/bumble/host.py
+++ b/bumble/host.py
@@ -184,7 +184,7 @@ class Host(AbortableEventEmitter):
         self.long_term_key_provider = None
         self.link_key_provider = None
         self.pairing_io_capability_provider = None  # Classic only
-        self.snooper = None
+        self.snooper: Optional[Snooper] = None
 
         # Connect to the source and sink if specified
         if controller_source:
@@ -530,7 +530,9 @@ class Host(AbortableEventEmitter):
 
                 # Check the return parameters if required
                 if check_result:
-                    if isinstance(response.return_parameters, int):
+                    if isinstance(response, hci.HCI_Command_Status_Event):
+                        status = response.status
+                    elif isinstance(response.return_parameters, int):
                         status = response.return_parameters
                     elif isinstance(response.return_parameters, bytes):
                         # return parameters first field is a one byte status code
@@ -719,14 +721,16 @@ class Host(AbortableEventEmitter):
         for connection_handle, num_completed_packets in zip(
             event.connection_handles, event.num_completed_packets
         ):
-            if not (connection := self.connections.get(connection_handle)):
+            if connection := self.connections.get(connection_handle):
+                connection.acl_packet_queue.on_packets_completed(num_completed_packets)
+            elif not (
+                self.cis_links.get(connection_handle)
+                or self.sco_links.get(connection_handle)
+            ):
                 logger.warning(
                     'received packet completion event for unknown handle '
                     f'0x{connection_handle:04X}'
                 )
-                continue
-
-            connection.acl_packet_queue.on_packets_completed(num_completed_packets)
 
     # Classic only
     def on_hci_connection_request_event(self, event):
diff --git a/bumble/keys.py b/bumble/keys.py
index 198d5c4..facaa37 100644
--- a/bumble/keys.py
+++ b/bumble/keys.py
@@ -25,7 +25,8 @@ import asyncio
 import logging
 import os
 import json
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type
+from typing_extensions import Self
 
 from .colors import color
 from .hci import Address
@@ -128,10 +129,10 @@ class PairingKeys:
 
     def print(self, prefix=''):
         keys_dict = self.to_dict()
-        for (container_property, value) in keys_dict.items():
+        for container_property, value in keys_dict.items():
             if isinstance(value, dict):
                 print(f'{prefix}{color(container_property, "cyan")}:')
-                for (key_property, key_value) in value.items():
+                for key_property, key_value in value.items():
                     print(f'{prefix}  {color(key_property, "green")}: {key_value}')
             else:
                 print(f'{prefix}{color(container_property, "cyan")}: {value}')
@@ -158,7 +159,7 @@ class KeyStore:
     async def get_resolving_keys(self):
         all_keys = await self.get_all()
         resolving_keys = []
-        for (name, keys) in all_keys:
+        for name, keys in all_keys:
             if keys.irk is not None:
                 if keys.address_type is None:
                     address_type = Address.RANDOM_DEVICE_ADDRESS
@@ -171,7 +172,7 @@ class KeyStore:
     async def print(self, prefix=''):
         entries = await self.get_all()
         separator = ''
-        for (name, keys) in entries:
+        for name, keys in entries:
             print(separator + prefix + color(name, 'yellow'))
             keys.print(prefix=prefix + '  ')
             separator = '\n'
@@ -253,8 +254,10 @@ class JsonKeyStore(KeyStore):
 
         logger.debug(f'JSON keystore: {self.filename}')
 
-    @staticmethod
-    def from_device(device: Device, filename=None) -> Optional[JsonKeyStore]:
+    @classmethod
+    def from_device(
+        cls: Type[Self], device: Device, filename: Optional[str] = None
+    ) -> Self:
         if not filename:
             # Extract the filename from the config if there is one
             if device.config.keystore is not None:
@@ -270,7 +273,7 @@ class JsonKeyStore(KeyStore):
         else:
             namespace = JsonKeyStore.DEFAULT_NAMESPACE
 
-        return JsonKeyStore(namespace, filename)
+        return cls(namespace, filename)
 
     async def load(self):
         # Try to open the file, without failing. If the file does not exist, it
diff --git a/bumble/l2cap.py b/bumble/l2cap.py
index cec14b8..b4f0121 100644
--- a/bumble/l2cap.py
+++ b/bumble/l2cap.py
@@ -70,6 +70,7 @@ L2CAP_LE_SIGNALING_CID = 0x05
 
 L2CAP_MIN_LE_MTU     = 23
 L2CAP_MIN_BR_EDR_MTU = 48
+L2CAP_MAX_BR_EDR_MTU = 65535
 
 L2CAP_DEFAULT_MTU = 2048  # Default value for the MTU we are willing to accept
 
@@ -832,7 +833,9 @@ class ClassicChannel(EventEmitter):
 
         # Wait for the connection to succeed or fail
         try:
-            return await self.connection_result
+            return await self.connection.abort_on(
+                'disconnection', self.connection_result
+            )
         finally:
             self.connection_result = None
 
@@ -2225,7 +2228,7 @@ class ChannelManager:
         # Connect
         try:
             await channel.connect()
-        except Exception as e:
+        except BaseException as e:
             del connection_channels[source_cid]
             raise e
 
diff --git a/bumble/pandora/host.py b/bumble/pandora/host.py
index e54d2d5..4904274 100644
--- a/bumble/pandora/host.py
+++ b/bumble/pandora/host.py
@@ -287,9 +287,9 @@ class HostService(HostServicer):
         self.log.debug(f"WaitDisconnection: {connection_handle}")
 
         if connection := self.device.lookup_connection(connection_handle):
-            disconnection_future: asyncio.Future[
-                None
-            ] = asyncio.get_running_loop().create_future()
+            disconnection_future: asyncio.Future[None] = (
+                asyncio.get_running_loop().create_future()
+            )
 
             def on_disconnection(_: None) -> None:
                 disconnection_future.set_result(None)
@@ -370,9 +370,9 @@ class HostService(HostServicer):
             scan_response_data=scan_response_data,
         )
 
-        pending_connection: asyncio.Future[
-            bumble.device.Connection
-        ] = asyncio.get_running_loop().create_future()
+        pending_connection: asyncio.Future[bumble.device.Connection] = (
+            asyncio.get_running_loop().create_future()
+        )
 
         if request.connectable:
 
@@ -516,9 +516,9 @@ class HostService(HostServicer):
                     await asyncio.sleep(1)
                     continue
 
-                pending_connection: asyncio.Future[
-                    bumble.device.Connection
-                ] = asyncio.get_running_loop().create_future()
+                pending_connection: asyncio.Future[bumble.device.Connection] = (
+                    asyncio.get_running_loop().create_future()
+                )
 
                 self.log.debug('Wait for LE connection...')
                 connection = await pending_connection
@@ -563,12 +563,14 @@ class HostService(HostServicer):
             legacy=request.legacy,
             active=not request.passive,
             own_address_type=request.own_address_type,
-            scan_interval=int(request.interval)
-            if request.interval
-            else DEVICE_DEFAULT_SCAN_INTERVAL,
-            scan_window=int(request.window)
-            if request.window
-            else DEVICE_DEFAULT_SCAN_WINDOW,
+            scan_interval=(
+                int(request.interval)
+                if request.interval
+                else DEVICE_DEFAULT_SCAN_INTERVAL
+            ),
+            scan_window=(
+                int(request.window) if request.window else DEVICE_DEFAULT_SCAN_WINDOW
+            ),
             scanning_phys=scanning_phys,
         )
 
@@ -782,9 +784,11 @@ class HostService(HostServicer):
                             *struct.pack('<H', dt.peripheral_connection_interval_min),
                             *struct.pack(
                                 '<H',
-                                dt.peripheral_connection_interval_max
-                                if dt.peripheral_connection_interval_max
-                                else dt.peripheral_connection_interval_min,
+                                (
+                                    dt.peripheral_connection_interval_max
+                                    if dt.peripheral_connection_interval_max
+                                    else dt.peripheral_connection_interval_min
+                                ),
                             ),
                         ]
                     ),
diff --git a/bumble/pandora/security.py b/bumble/pandora/security.py
index b36fb18..2cbb78a 100644
--- a/bumble/pandora/security.py
+++ b/bumble/pandora/security.py
@@ -383,9 +383,9 @@ class SecurityService(SecurityServicer):
             connection.transport
         ] == request.level_variant()
 
-        wait_for_security: asyncio.Future[
-            str
-        ] = asyncio.get_running_loop().create_future()
+        wait_for_security: asyncio.Future[str] = (
+            asyncio.get_running_loop().create_future()
+        )
         authenticate_task: Optional[asyncio.Future[None]] = None
         pair_task: Optional[asyncio.Future[None]] = None
 
diff --git a/bumble/profiles/bap.py b/bumble/profiles/bap.py
index dd57f01..c0123b1 100644
--- a/bumble/profiles/bap.py
+++ b/bumble/profiles/bap.py
@@ -24,8 +24,9 @@ import enum
 import struct
 import functools
 import logging
-from typing import Optional, List, Union, Type, Dict, Any, Tuple, cast
+from typing import Optional, List, Union, Type, Dict, Any, Tuple
 
+from bumble import core
 from bumble import colors
 from bumble import device
 from bumble import hci
@@ -77,6 +78,10 @@ class AudioLocation(enum.IntFlag):
     LEFT_SURROUND           = 0x04000000
     RIGHT_SURROUND          = 0x08000000
 
+    @property
+    def channel_count(self) -> int:
+        return bin(self.value).count('1')
+
 
 class AudioInputType(enum.IntEnum):
     '''Bluetooth Assigned Numbers, Section 6.12.2 - Audio Input Type'''
@@ -217,6 +222,13 @@ class FrameDuration(enum.IntEnum):
     DURATION_7500_US  = 0x00
     DURATION_10000_US = 0x01
 
+    @property
+    def us(self) -> int:
+        return {
+            FrameDuration.DURATION_7500_US: 7500,
+            FrameDuration.DURATION_10000_US: 10000,
+        }[self]
+
 
 class SupportedFrameDuration(enum.IntFlag):
     '''Bluetooth Assigned Numbers, Section 6.12.4.2 - Frame Duration'''
@@ -228,6 +240,14 @@ class SupportedFrameDuration(enum.IntFlag):
     DURATION_10000_US_PREFERRED = 0b0010
 
 
+class AnnouncementType(enum.IntEnum):
+    '''Basic Audio Profile, 3.5.3. Additional Audio Stream Control Service requirements'''
+
+    # fmt: off
+    GENERAL  = 0x00
+    TARGETED = 0x01
+
+
 # -----------------------------------------------------------------------------
 # ASE Operations
 # -----------------------------------------------------------------------------
@@ -453,6 +473,34 @@ class AudioRole(enum.IntEnum):
     SOURCE = hci.HCI_LE_Setup_ISO_Data_Path_Command.Direction.HOST_TO_CONTROLLER
 
 
+@dataclasses.dataclass
+class UnicastServerAdvertisingData:
+    """Advertising Data for ASCS."""
+
+    announcement_type: AnnouncementType = AnnouncementType.TARGETED
+    available_audio_contexts: ContextType = ContextType.MEDIA
+    metadata: bytes = b''
+
+    def __bytes__(self) -> bytes:
+        return bytes(
+            core.AdvertisingData(
+                [
+                    (
+                        core.AdvertisingData.SERVICE_DATA_16_BIT_UUID,
+                        struct.pack(
+                            '<2sBIB',
+                            gatt.GATT_AUDIO_STREAM_CONTROL_SERVICE.to_bytes(),
+                            self.announcement_type,
+                            self.available_audio_contexts,
+                            len(self.metadata),
+                        )
+                        + self.metadata,
+                    )
+                ]
+            )
+        )
+
+
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
@@ -497,7 +545,7 @@ class CodecSpecificCapabilities:
 
     supported_sampling_frequencies: SupportedSamplingFrequency
     supported_frame_durations: SupportedFrameDuration
-    supported_audio_channel_counts: Sequence[int]
+    supported_audio_channel_count: Sequence[int]
     min_octets_per_codec_frame: int
     max_octets_per_codec_frame: int
     supported_max_codec_frames_per_sdu: int
@@ -506,7 +554,7 @@ class CodecSpecificCapabilities:
     def from_bytes(cls, data: bytes) -> CodecSpecificCapabilities:
         offset = 0
         # Allowed default values.
-        supported_audio_channel_counts = [1]
+        supported_audio_channel_count = [1]
         supported_max_codec_frames_per_sdu = 1
         while offset < len(data):
             length, type = struct.unpack_from('BB', data, offset)
@@ -519,7 +567,7 @@ class CodecSpecificCapabilities:
             elif type == CodecSpecificCapabilities.Type.FRAME_DURATION:
                 supported_frame_durations = SupportedFrameDuration(value)
             elif type == CodecSpecificCapabilities.Type.AUDIO_CHANNEL_COUNT:
-                supported_audio_channel_counts = bits_to_channel_counts(value)
+                supported_audio_channel_count = bits_to_channel_counts(value)
             elif type == CodecSpecificCapabilities.Type.OCTETS_PER_FRAME:
                 min_octets_per_sample = value & 0xFFFF
                 max_octets_per_sample = value >> 16
@@ -530,7 +578,7 @@ class CodecSpecificCapabilities:
         return CodecSpecificCapabilities(
             supported_sampling_frequencies=supported_sampling_frequencies,
             supported_frame_durations=supported_frame_durations,
-            supported_audio_channel_counts=supported_audio_channel_counts,
+            supported_audio_channel_count=supported_audio_channel_count,
             min_octets_per_codec_frame=min_octets_per_sample,
             max_octets_per_codec_frame=max_octets_per_sample,
             supported_max_codec_frames_per_sdu=supported_max_codec_frames_per_sdu,
@@ -547,7 +595,7 @@ class CodecSpecificCapabilities:
             self.supported_frame_durations,
             2,
             CodecSpecificCapabilities.Type.AUDIO_CHANNEL_COUNT,
-            channel_counts_to_bits(self.supported_audio_channel_counts),
+            channel_counts_to_bits(self.supported_audio_channel_count),
             5,
             CodecSpecificCapabilities.Type.OCTETS_PER_FRAME,
             self.min_octets_per_codec_frame,
@@ -833,15 +881,22 @@ class AseStateMachine(gatt.Characteristic):
         cig_id: int,
         cis_id: int,
     ) -> None:
-        if cis_id == self.cis_id and self.state == self.State.ENABLING:
+        if (
+            cig_id == self.cig_id
+            and cis_id == self.cis_id
+            and self.state == self.State.ENABLING
+        ):
             acl_connection.abort_on(
                 'flush', self.service.device.accept_cis_request(cis_handle)
             )
 
     def on_cis_establishment(self, cis_link: device.CisLink) -> None:
-        if cis_link.cis_id == self.cis_id and self.state == self.State.ENABLING:
-            self.state = self.State.STREAMING
-            self.cis_link = cis_link
+        if (
+            cis_link.cig_id == self.cig_id
+            and cis_link.cis_id == self.cis_id
+            and self.state == self.State.ENABLING
+        ):
+            cis_link.on('disconnection', self.on_cis_disconnection)
 
             async def post_cis_established():
                 await self.service.device.send_command(
@@ -854,9 +909,15 @@ class AseStateMachine(gatt.Characteristic):
                         codec_configuration=b'',
                     )
                 )
+                if self.role == AudioRole.SINK:
+                    self.state = self.State.STREAMING
                 await self.service.device.notify_subscribers(self, self.value)
 
             cis_link.acl_connection.abort_on('flush', post_cis_established())
+            self.cis_link = cis_link
+
+    def on_cis_disconnection(self, _reason) -> None:
+        self.cis_link = None
 
     def on_config_codec(
         self,
@@ -954,11 +1015,17 @@ class AseStateMachine(gatt.Characteristic):
                 AseResponseCode.INVALID_ASE_STATE_MACHINE_TRANSITION,
                 AseReasonCode.NONE,
             )
-        self.state = self.State.DISABLING
+        if self.role == AudioRole.SINK:
+            self.state = self.State.QOS_CONFIGURED
+        else:
+            self.state = self.State.DISABLING
         return (AseResponseCode.SUCCESS, AseReasonCode.NONE)
 
     def on_receiver_stop_ready(self) -> Tuple[AseResponseCode, AseReasonCode]:
-        if self.state != AseStateMachine.State.DISABLING:
+        if (
+            self.role != AudioRole.SOURCE
+            or self.state != AseStateMachine.State.DISABLING
+        ):
             return (
                 AseResponseCode.INVALID_ASE_STATE_MACHINE_TRANSITION,
                 AseReasonCode.NONE,
@@ -1009,6 +1076,7 @@ class AseStateMachine(gatt.Characteristic):
     def state(self, new_state: State) -> None:
         logger.debug(f'{self} state change -> {colors.color(new_state.name, "cyan")}')
         self._state = new_state
+        self.emit('state_change')
 
     @property
     def value(self):
@@ -1081,6 +1149,7 @@ class AudioStreamControlService(gatt.TemplateService):
 
     ase_state_machines: Dict[int, AseStateMachine]
     ase_control_point: gatt.Characteristic
+    _active_client: Optional[device.Connection] = None
 
     def __init__(
         self,
@@ -1118,7 +1187,16 @@ class AudioStreamControlService(gatt.TemplateService):
         else:
             return (ase_id, AseResponseCode.INVALID_ASE_ID, AseReasonCode.NONE)
 
+    def _on_client_disconnected(self, _reason: int) -> None:
+        for ase in self.ase_state_machines.values():
+            ase.state = AseStateMachine.State.IDLE
+        self._active_client = None
+
     def on_write_ase_control_point(self, connection, data):
+        if not self._active_client and connection:
+            self._active_client = connection
+            connection.once('disconnection', self._on_client_disconnected)
+
         operation = ASE_Operation.from_bytes(data)
         responses = []
         logger.debug(f'*** ASCS Write {operation} ***')
diff --git a/bumble/profiles/device_information_service.py b/bumble/profiles/device_information_service.py
index 09bfd6c..ecb1c0f 100644
--- a/bumble/profiles/device_information_service.py
+++ b/bumble/profiles/device_information_service.py
@@ -19,8 +19,8 @@
 import struct
 from typing import Optional, Tuple
 
-from ..gatt_client import ProfileServiceProxy
-from ..gatt import (
+from bumble.gatt_client import ServiceProxy, ProfileServiceProxy, CharacteristicProxy
+from bumble.gatt import (
     GATT_DEVICE_INFORMATION_SERVICE,
     GATT_FIRMWARE_REVISION_STRING_CHARACTERISTIC,
     GATT_HARDWARE_REVISION_STRING_CHARACTERISTIC,
@@ -59,7 +59,7 @@ class DeviceInformationService(TemplateService):
         firmware_revision: Optional[str] = None,
         software_revision: Optional[str] = None,
         system_id: Optional[Tuple[int, int]] = None,  # (OUI, Manufacturer ID)
-        ieee_regulatory_certification_data_list: Optional[bytes] = None
+        ieee_regulatory_certification_data_list: Optional[bytes] = None,
         # TODO: pnp_id
     ):
         characteristics = [
@@ -104,10 +104,19 @@ class DeviceInformationService(TemplateService):
 class DeviceInformationServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = DeviceInformationService
 
-    def __init__(self, service_proxy):
+    manufacturer_name: Optional[UTF8CharacteristicAdapter]
+    model_number: Optional[UTF8CharacteristicAdapter]
+    serial_number: Optional[UTF8CharacteristicAdapter]
+    hardware_revision: Optional[UTF8CharacteristicAdapter]
+    firmware_revision: Optional[UTF8CharacteristicAdapter]
+    software_revision: Optional[UTF8CharacteristicAdapter]
+    system_id: Optional[DelegatedCharacteristicAdapter]
+    ieee_regulatory_certification_data_list: Optional[CharacteristicProxy]
+
+    def __init__(self, service_proxy: ServiceProxy):
         self.service_proxy = service_proxy
 
-        for (field, uuid) in (
+        for field, uuid in (
             ('manufacturer_name', GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC),
             ('model_number', GATT_MODEL_NUMBER_STRING_CHARACTERISTIC),
             ('serial_number', GATT_SERIAL_NUMBER_STRING_CHARACTERISTIC),
diff --git a/bumble/rfcomm.py b/bumble/rfcomm.py
index 6ca0f50..2d8a627 100644
--- a/bumble/rfcomm.py
+++ b/bumble/rfcomm.py
@@ -19,6 +19,7 @@ from __future__ import annotations
 
 import logging
 import asyncio
+import collections
 import dataclasses
 import enum
 from typing import Callable, Dict, List, Optional, Tuple, Union, TYPE_CHECKING
@@ -54,6 +55,7 @@ logger = logging.getLogger(__name__)
 # fmt: off
 
 RFCOMM_PSM = 0x0003
+DEFAULT_RX_QUEUE_SIZE = 32
 
 class FrameType(enum.IntEnum):
     SABM = 0x2F  # Control field [1,1,1,1,_,1,0,0] LSB-first
@@ -104,9 +106,11 @@ CRC_TABLE = bytes([
     0XBA, 0X2B, 0X59, 0XC8, 0XBD, 0X2C, 0X5E, 0XCF
 ])
 
-RFCOMM_DEFAULT_L2CAP_MTU      = 2048
-RFCOMM_DEFAULT_WINDOW_SIZE    = 7
-RFCOMM_DEFAULT_MAX_FRAME_SIZE = 2000
+RFCOMM_DEFAULT_L2CAP_MTU        = 2048
+RFCOMM_DEFAULT_INITIAL_CREDITS  = 7
+RFCOMM_DEFAULT_MAX_CREDITS      = 32
+RFCOMM_DEFAULT_CREDIT_THRESHOLD = RFCOMM_DEFAULT_MAX_CREDITS // 2
+RFCOMM_DEFAULT_MAX_FRAME_SIZE   = 2000
 
 RFCOMM_DYNAMIC_CHANNEL_NUMBER_START = 1
 RFCOMM_DYNAMIC_CHANNEL_NUMBER_END   = 30
@@ -363,12 +367,12 @@ class RFCOMM_MCC_PN:
     ack_timer: int
     max_frame_size: int
     max_retransmissions: int
-    window_size: int
+    initial_credits: int
 
     def __post_init__(self) -> None:
-        if self.window_size < 1 or self.window_size > 7:
+        if self.initial_credits < 1 or self.initial_credits > 7:
             logger.warning(
-                f'Error Recovery Window size {self.window_size} is out of range [1, 7].'
+                f'Initial credits {self.initial_credits} is out of range [1, 7].'
             )
 
     @staticmethod
@@ -380,7 +384,7 @@ class RFCOMM_MCC_PN:
             ack_timer=data[3],
             max_frame_size=data[4] | data[5] << 8,
             max_retransmissions=data[6],
-            window_size=data[7] & 0x07,
+            initial_credits=data[7] & 0x07,
         )
 
     def __bytes__(self) -> bytes:
@@ -394,7 +398,7 @@ class RFCOMM_MCC_PN:
                 (self.max_frame_size >> 8) & 0xFF,
                 self.max_retransmissions & 0xFF,
                 # Only 3 bits are meaningful.
-                self.window_size & 0x07,
+                self.initial_credits & 0x07,
             ]
         )
 
@@ -444,39 +448,58 @@ class DLC(EventEmitter):
         DISCONNECTED = 0x04
         RESET = 0x05
 
-    connection_result: Optional[asyncio.Future]
-    sink: Optional[Callable[[bytes], None]]
-
     def __init__(
         self,
         multiplexer: Multiplexer,
         dlci: int,
-        max_frame_size: int,
-        window_size: int,
+        tx_max_frame_size: int,
+        tx_initial_credits: int,
+        rx_max_frame_size: int,
+        rx_initial_credits: int,
     ) -> None:
         super().__init__()
         self.multiplexer = multiplexer
         self.dlci = dlci
-        self.max_frame_size = max_frame_size
-        self.window_size = window_size
-        self.rx_credits = window_size
-        self.rx_threshold = window_size // 2
-        self.tx_credits = window_size
+        self.rx_max_frame_size = rx_max_frame_size
+        self.rx_initial_credits = rx_initial_credits
+        self.rx_max_credits = RFCOMM_DEFAULT_MAX_CREDITS
+        self.rx_credits = rx_initial_credits
+        self.rx_credits_threshold = RFCOMM_DEFAULT_CREDIT_THRESHOLD
+        self.tx_max_frame_size = tx_max_frame_size
+        self.tx_credits = tx_initial_credits
         self.tx_buffer = b''
         self.state = DLC.State.INIT
         self.role = multiplexer.role
         self.c_r = 1 if self.role == Multiplexer.Role.INITIATOR else 0
-        self.sink = None
-        self.connection_result = None
+        self.connection_result: Optional[asyncio.Future] = None
+        self.disconnection_result: Optional[asyncio.Future] = None
         self.drained = asyncio.Event()
         self.drained.set()
+        # Queued packets when sink is not set.
+        self._enqueued_rx_packets: collections.deque[bytes] = collections.deque(
+            maxlen=DEFAULT_RX_QUEUE_SIZE
+        )
+        self._sink: Optional[Callable[[bytes], None]] = None
 
         # Compute the MTU
         max_overhead = 4 + 1  # header with 2-byte length + fcs
         self.mtu = min(
-            max_frame_size, self.multiplexer.l2cap_channel.peer_mtu - max_overhead
+            tx_max_frame_size, self.multiplexer.l2cap_channel.peer_mtu - max_overhead
         )
 
+    @property
+    def sink(self) -> Optional[Callable[[bytes], None]]:
+        return self._sink
+
+    @sink.setter
+    def sink(self, sink: Optional[Callable[[bytes], None]]) -> None:
+        self._sink = sink
+        # Dump queued packets to sink
+        if sink:
+            for packet in self._enqueued_rx_packets:
+                sink(packet)  # pylint: disable=not-callable
+            self._enqueued_rx_packets.clear()
+
     def change_state(self, new_state: State) -> None:
         logger.debug(f'{self} state change -> {color(new_state.name, "magenta")}')
         self.state = new_state
@@ -507,20 +530,35 @@ class DLC(EventEmitter):
         self.emit('open')
 
     def on_ua_frame(self, _frame: RFCOMM_Frame) -> None:
-        if self.state != DLC.State.CONNECTING:
+        if self.state == DLC.State.CONNECTING:
+            # Exchange the modem status with the peer
+            msc = RFCOMM_MCC_MSC(dlci=self.dlci, fc=0, rtc=1, rtr=1, ic=0, dv=1)
+            mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.MSC, c_r=1, data=bytes(msc))
+            logger.debug(f'>>> MCC MSC Command: {msc}')
+            self.send_frame(RFCOMM_Frame.uih(c_r=self.c_r, dlci=0, information=mcc))
+
+            self.change_state(DLC.State.CONNECTED)
+            if self.connection_result:
+                self.connection_result.set_result(None)
+                self.connection_result = None
+            self.multiplexer.on_dlc_open_complete(self)
+        elif self.state == DLC.State.DISCONNECTING:
+            self.change_state(DLC.State.DISCONNECTED)
+            if self.disconnection_result:
+                self.disconnection_result.set_result(None)
+                self.disconnection_result = None
+            self.multiplexer.on_dlc_disconnection(self)
+            self.emit('close')
+        else:
             logger.warning(
-                color('!!! received SABM when not in CONNECTING state', 'red')
+                color(
+                    (
+                        '!!! received UA frame when not in '
+                        'CONNECTING or DISCONNECTING state'
+                    ),
+                    'red',
+                )
             )
-            return
-
-        # Exchange the modem status with the peer
-        msc = RFCOMM_MCC_MSC(dlci=self.dlci, fc=0, rtc=1, rtr=1, ic=0, dv=1)
-        mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.MSC, c_r=1, data=bytes(msc))
-        logger.debug(f'>>> MCC MSC Command: {msc}')
-        self.send_frame(RFCOMM_Frame.uih(c_r=self.c_r, dlci=0, information=mcc))
-
-        self.change_state(DLC.State.CONNECTED)
-        self.multiplexer.on_dlc_open_complete(self)
 
     def on_dm_frame(self, frame: RFCOMM_Frame) -> None:
         # TODO: handle all states
@@ -549,8 +587,15 @@ class DLC(EventEmitter):
             f'rx_credits={self.rx_credits}: {data.hex()}'
         )
         if data:
-            if self.sink:
-                self.sink(data)  # pylint: disable=not-callable
+            if self._sink:
+                self._sink(data)  # pylint: disable=not-callable
+            else:
+                self._enqueued_rx_packets.append(data)
+            if (
+                self._enqueued_rx_packets.maxlen
+                and len(self._enqueued_rx_packets) >= self._enqueued_rx_packets.maxlen
+            ):
+                logger.warning(f'DLC [{self.dlci}] received packet queue is full')
 
             # Update the credits
             if self.rx_credits > 0:
@@ -584,6 +629,19 @@ class DLC(EventEmitter):
         self.connection_result = asyncio.get_running_loop().create_future()
         self.send_frame(RFCOMM_Frame.sabm(c_r=self.c_r, dlci=self.dlci))
 
+    async def disconnect(self) -> None:
+        if self.state != DLC.State.CONNECTED:
+            raise InvalidStateError('invalid state')
+
+        self.disconnection_result = asyncio.get_running_loop().create_future()
+        self.change_state(DLC.State.DISCONNECTING)
+        self.send_frame(
+            RFCOMM_Frame.disc(
+                c_r=1 if self.role == Multiplexer.Role.INITIATOR else 0, dlci=self.dlci
+            )
+        )
+        await self.disconnection_result
+
     def accept(self) -> None:
         if self.state != DLC.State.INIT:
             raise InvalidStateError('invalid state')
@@ -593,9 +651,9 @@ class DLC(EventEmitter):
             cl=0xE0,
             priority=7,
             ack_timer=0,
-            max_frame_size=self.max_frame_size,
+            max_frame_size=self.rx_max_frame_size,
             max_retransmissions=0,
-            window_size=self.window_size,
+            initial_credits=self.rx_initial_credits,
         )
         mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.PN, c_r=0, data=bytes(pn))
         logger.debug(f'>>> PN Response: {pn}')
@@ -603,8 +661,8 @@ class DLC(EventEmitter):
         self.change_state(DLC.State.CONNECTING)
 
     def rx_credits_needed(self) -> int:
-        if self.rx_credits <= self.rx_threshold:
-            return self.window_size - self.rx_credits
+        if self.rx_credits <= self.rx_credits_threshold:
+            return self.rx_max_credits - self.rx_credits
 
         return 0
 
@@ -664,6 +722,17 @@ class DLC(EventEmitter):
     async def drain(self) -> None:
         await self.drained.wait()
 
+    def abort(self) -> None:
+        logger.debug(f'aborting DLC: {self}')
+        if self.connection_result:
+            self.connection_result.cancel()
+            self.connection_result = None
+        if self.disconnection_result:
+            self.disconnection_result.cancel()
+            self.disconnection_result = None
+        self.change_state(DLC.State.RESET)
+        self.emit('close')
+
     def __str__(self) -> str:
         return f'DLC(dlci={self.dlci},state={self.state.name})'
 
@@ -686,7 +755,7 @@ class Multiplexer(EventEmitter):
     connection_result: Optional[asyncio.Future]
     disconnection_result: Optional[asyncio.Future]
     open_result: Optional[asyncio.Future]
-    acceptor: Optional[Callable[[int], bool]]
+    acceptor: Optional[Callable[[int], Optional[Tuple[int, int]]]]
     dlcs: Dict[int, DLC]
 
     def __init__(self, l2cap_channel: l2cap.ClassicChannel, role: Role) -> None:
@@ -698,11 +767,15 @@ class Multiplexer(EventEmitter):
         self.connection_result = None
         self.disconnection_result = None
         self.open_result = None
+        self.open_pn: Optional[RFCOMM_MCC_PN] = None
+        self.open_rx_max_credits = 0
         self.acceptor = None
 
         # Become a sink for the L2CAP channel
         l2cap_channel.sink = self.on_pdu
 
+        l2cap_channel.on('close', self.on_l2cap_channel_close)
+
     def change_state(self, new_state: State) -> None:
         logger.debug(f'{self} state change -> {color(new_state.name, "cyan")}')
         self.state = new_state
@@ -766,6 +839,7 @@ class Multiplexer(EventEmitter):
                         'rfcomm',
                     )
                 )
+                self.open_result = None
         else:
             logger.warning(f'unexpected state for DM: {self}')
 
@@ -803,9 +877,16 @@ class Multiplexer(EventEmitter):
             else:
                 if self.acceptor:
                     channel_number = pn.dlci >> 1
-                    if self.acceptor(channel_number):
+                    if dlc_params := self.acceptor(channel_number):
                         # Create a new DLC
-                        dlc = DLC(self, pn.dlci, pn.max_frame_size, pn.window_size)
+                        dlc = DLC(
+                            self,
+                            dlci=pn.dlci,
+                            tx_max_frame_size=pn.max_frame_size,
+                            tx_initial_credits=pn.initial_credits,
+                            rx_max_frame_size=dlc_params[0],
+                            rx_initial_credits=dlc_params[1],
+                        )
                         self.dlcs[pn.dlci] = dlc
 
                         # Re-emit the handshake completion event
@@ -823,8 +904,17 @@ class Multiplexer(EventEmitter):
             # Response
             logger.debug(f'>>> PN Response: {pn}')
             if self.state == Multiplexer.State.OPENING:
-                dlc = DLC(self, pn.dlci, pn.max_frame_size, pn.window_size)
+                assert self.open_pn
+                dlc = DLC(
+                    self,
+                    dlci=pn.dlci,
+                    tx_max_frame_size=pn.max_frame_size,
+                    tx_initial_credits=pn.initial_credits,
+                    rx_max_frame_size=self.open_pn.max_frame_size,
+                    rx_initial_credits=self.open_pn.initial_credits,
+                )
                 self.dlcs[pn.dlci] = dlc
+                self.open_pn = None
                 dlc.connect()
             else:
                 logger.warning('ignoring PN response')
@@ -862,7 +952,7 @@ class Multiplexer(EventEmitter):
         self,
         channel: int,
         max_frame_size: int = RFCOMM_DEFAULT_MAX_FRAME_SIZE,
-        window_size: int = RFCOMM_DEFAULT_WINDOW_SIZE,
+        initial_credits: int = RFCOMM_DEFAULT_INITIAL_CREDITS,
     ) -> DLC:
         if self.state != Multiplexer.State.CONNECTED:
             if self.state == Multiplexer.State.OPENING:
@@ -870,17 +960,19 @@ class Multiplexer(EventEmitter):
 
             raise InvalidStateError('not connected')
 
-        pn = RFCOMM_MCC_PN(
+        self.open_pn = RFCOMM_MCC_PN(
             dlci=channel << 1,
             cl=0xF0,
             priority=7,
             ack_timer=0,
             max_frame_size=max_frame_size,
             max_retransmissions=0,
-            window_size=window_size,
+            initial_credits=initial_credits,
         )
-        mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.PN, c_r=1, data=bytes(pn))
-        logger.debug(f'>>> Sending MCC: {pn}')
+        mcc = RFCOMM_Frame.make_mcc(
+            mcc_type=MccType.PN, c_r=1, data=bytes(self.open_pn)
+        )
+        logger.debug(f'>>> Sending MCC: {self.open_pn}')
         self.open_result = asyncio.get_running_loop().create_future()
         self.change_state(Multiplexer.State.OPENING)
         self.send_frame(
@@ -890,15 +982,31 @@ class Multiplexer(EventEmitter):
                 information=mcc,
             )
         )
-        result = await self.open_result
-        self.open_result = None
-        return result
+        return await self.open_result
 
     def on_dlc_open_complete(self, dlc: DLC) -> None:
         logger.debug(f'DLC [{dlc.dlci}] open complete')
+
         self.change_state(Multiplexer.State.CONNECTED)
+
         if self.open_result:
             self.open_result.set_result(dlc)
+            self.open_result = None
+
+    def on_dlc_disconnection(self, dlc: DLC) -> None:
+        logger.debug(f'DLC [{dlc.dlci}] disconnection')
+        self.dlcs.pop(dlc.dlci, None)
+
+    def on_l2cap_channel_close(self) -> None:
+        logger.debug('L2CAP channel closed, cleaning up')
+        if self.open_result:
+            self.open_result.cancel()
+            self.open_result = None
+        if self.disconnection_result:
+            self.disconnection_result.cancel()
+            self.disconnection_result = None
+        for dlc in self.dlcs.values():
+            dlc.abort()
 
     def __str__(self) -> str:
         return f'Multiplexer(state={self.state.name})'
@@ -957,15 +1065,13 @@ class Client:
 
 # -----------------------------------------------------------------------------
 class Server(EventEmitter):
-    acceptors: Dict[int, Callable[[DLC], None]]
-
     def __init__(
         self, device: Device, l2cap_mtu: int = RFCOMM_DEFAULT_L2CAP_MTU
     ) -> None:
         super().__init__()
         self.device = device
-        self.multiplexer = None
-        self.acceptors = {}
+        self.acceptors: Dict[int, Callable[[DLC], None]] = {}
+        self.dlc_configs: Dict[int, Tuple[int, int]] = {}
 
         # Register ourselves with the L2CAP channel manager
         self.l2cap_server = device.create_l2cap_server(
@@ -973,7 +1079,13 @@ class Server(EventEmitter):
             handler=self.on_connection,
         )
 
-    def listen(self, acceptor: Callable[[DLC], None], channel: int = 0) -> int:
+    def listen(
+        self,
+        acceptor: Callable[[DLC], None],
+        channel: int = 0,
+        max_frame_size: int = RFCOMM_DEFAULT_MAX_FRAME_SIZE,
+        initial_credits: int = RFCOMM_DEFAULT_INITIAL_CREDITS,
+    ) -> int:
         if channel:
             if channel in self.acceptors:
                 # Busy
@@ -993,6 +1105,8 @@ class Server(EventEmitter):
                 return 0
 
         self.acceptors[channel] = acceptor
+        self.dlc_configs[channel] = (max_frame_size, initial_credits)
+
         return channel
 
     def on_connection(self, l2cap_channel: l2cap.ClassicChannel) -> None:
@@ -1010,15 +1124,14 @@ class Server(EventEmitter):
         # Notify
         self.emit('start', multiplexer)
 
-    def accept_dlc(self, channel_number: int) -> bool:
-        return channel_number in self.acceptors
+    def accept_dlc(self, channel_number: int) -> Optional[Tuple[int, int]]:
+        return self.dlc_configs.get(channel_number)
 
     def on_dlc(self, dlc: DLC) -> None:
         logger.debug(f'@@@ new DLC connected: {dlc}')
 
         # Let the acceptor know
-        acceptor = self.acceptors.get(dlc.dlci >> 1)
-        if acceptor:
+        if acceptor := self.acceptors.get(dlc.dlci >> 1):
             acceptor(dlc)
 
     def __enter__(self) -> Self:
diff --git a/bumble/sdp.py b/bumble/sdp.py
index 6423790..543c322 100644
--- a/bumble/sdp.py
+++ b/bumble/sdp.py
@@ -825,11 +825,13 @@ class Client:
         )
         attribute_id_list = DataElement.sequence(
             [
-                DataElement.unsigned_integer(
-                    attribute_id[0], value_size=attribute_id[1]
+                (
+                    DataElement.unsigned_integer(
+                        attribute_id[0], value_size=attribute_id[1]
+                    )
+                    if isinstance(attribute_id, tuple)
+                    else DataElement.unsigned_integer_16(attribute_id)
                 )
-                if isinstance(attribute_id, tuple)
-                else DataElement.unsigned_integer_16(attribute_id)
                 for attribute_id in attribute_ids
             ]
         )
@@ -881,11 +883,13 @@ class Client:
 
         attribute_id_list = DataElement.sequence(
             [
-                DataElement.unsigned_integer(
-                    attribute_id[0], value_size=attribute_id[1]
+                (
+                    DataElement.unsigned_integer(
+                        attribute_id[0], value_size=attribute_id[1]
+                    )
+                    if isinstance(attribute_id, tuple)
+                    else DataElement.unsigned_integer_16(attribute_id)
                 )
-                if isinstance(attribute_id, tuple)
-                else DataElement.unsigned_integer_16(attribute_id)
                 for attribute_id in attribute_ids
             ]
         )
@@ -993,7 +997,7 @@ class Server:
             try:
                 handler(sdp_pdu)
             except Exception as error:
-                logger.warning(f'{color("!!! Exception in handler:", "red")} {error}')
+                logger.exception(f'{color("!!! Exception in handler:", "red")} {error}')
                 self.send_response(
                     SDP_ErrorResponse(
                         transaction_id=sdp_pdu.transaction_id,
diff --git a/bumble/smp.py b/bumble/smp.py
index 73fd439..3a88a31 100644
--- a/bumble/smp.py
+++ b/bumble/smp.py
@@ -737,9 +737,9 @@ class Session:
 
         # Create a future that can be used to wait for the session to complete
         if self.is_initiator:
-            self.pairing_result: Optional[
-                asyncio.Future[None]
-            ] = asyncio.get_running_loop().create_future()
+            self.pairing_result: Optional[asyncio.Future[None]] = (
+                asyncio.get_running_loop().create_future()
+            )
         else:
             self.pairing_result = None
 
diff --git a/bumble/transport/common.py b/bumble/transport/common.py
index ef35c9f..ffbf7b0 100644
--- a/bumble/transport/common.py
+++ b/bumble/transport/common.py
@@ -59,15 +59,13 @@ class TransportLostError(Exception):
 # Typing Protocols
 # -----------------------------------------------------------------------------
 class TransportSink(Protocol):
-    def on_packet(self, packet: bytes) -> None:
-        ...
+    def on_packet(self, packet: bytes) -> None: ...
 
 
 class TransportSource(Protocol):
     terminated: asyncio.Future[None]
 
-    def set_packet_sink(self, sink: TransportSink) -> None:
-        ...
+    def set_packet_sink(self, sink: TransportSink) -> None: ...
 
 
 # -----------------------------------------------------------------------------
@@ -427,6 +425,10 @@ class SnoopingTransport(Transport):
     class Source:
         sink: TransportSink
 
+        @property
+        def metadata(self) -> dict[str, Any]:
+            return getattr(self.source, 'metadata', {})
+
         def __init__(self, source: TransportSource, snooper: Snooper):
             self.source = source
             self.snooper = snooper
diff --git a/bumble/transport/pyusb.py b/bumble/transport/pyusb.py
index 61ce17e..68a1dfd 100644
--- a/bumble/transport/pyusb.py
+++ b/bumble/transport/pyusb.py
@@ -23,12 +23,25 @@ import time
 import usb.core
 import usb.util
 
+from typing import Optional
+from usb.core import Device as UsbDevice
+from usb.core import USBError
+from usb.util import CTRL_TYPE_CLASS, CTRL_RECIPIENT_OTHER
+from usb.legacy import REQ_SET_FEATURE, REQ_CLEAR_FEATURE, CLASS_HUB
+
 from .common import Transport, ParserSource
 from .. import hci
 from ..colors import color
 
 
 # -----------------------------------------------------------------------------
+# Constant
+# -----------------------------------------------------------------------------
+USB_PORT_FEATURE_POWER = 8
+POWER_CYCLE_DELAY = 1
+RESET_DELAY = 3
+
+# -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------
 logger = logging.getLogger(__name__)
@@ -214,6 +227,10 @@ async def open_pyusb_transport(spec: str) -> Transport:
         usb_find = libusb_package.find
 
     # Find the device according to the spec moniker
+    power_cycle = False
+    if spec.startswith('!'):
+        power_cycle = True
+        spec = spec[1:]
     if ':' in spec:
         vendor_id, product_id = spec.split(':')
         device = usb_find(idVendor=int(vendor_id, 16), idProduct=int(product_id, 16))
@@ -245,6 +262,14 @@ async def open_pyusb_transport(spec: str) -> Transport:
         raise ValueError('device not found')
     logger.debug(f'USB Device: {device}')
 
+    # Power Cycle the device
+    if power_cycle:
+        try:
+            device = await _power_cycle(device)  # type: ignore
+        except Exception as e:
+            logging.debug(e)
+            logging.info(f"Unable to power cycle {hex(device.idVendor)} {hex(device.idProduct)}")  # type: ignore
+
     # Collect the metadata
     device_metadata = {'vendor_id': device.idVendor, 'product_id': device.idProduct}
 
@@ -308,3 +333,73 @@ async def open_pyusb_transport(spec: str) -> Transport:
     packet_sink.start()
 
     return UsbTransport(device, packet_source, packet_sink)
+
+
+async def _power_cycle(device: UsbDevice) -> UsbDevice:
+    """
+    For devices connected to compatible USB hubs: Performs a power cycle on a given USB device.
+    This involves temporarily disabling its port on the hub and then re-enabling it.
+    """
+    device_path = f'{device.bus}-{".".join(map(str, device.port_numbers))}'  # type: ignore
+    hub = _find_hub_by_device_path(device_path)
+
+    if hub:
+        try:
+            device_port = device.port_numbers[-1]  # type: ignore
+            _set_port_status(hub, device_port, False)
+            await asyncio.sleep(POWER_CYCLE_DELAY)
+            _set_port_status(hub, device_port, True)
+            await asyncio.sleep(RESET_DELAY)
+
+            # Device needs to be find again otherwise it will appear as disconnected
+            return usb.core.find(idVendor=device.idVendor, idProduct=device.idProduct)  # type: ignore
+        except USBError as e:
+            logger.error(f"Adjustment needed: Please revise the udev rule for device {hex(device.idVendor)}:{hex(device.idProduct)} for proper recognition.")  # type: ignore
+            logger.error(e)
+
+    return device
+
+
+def _set_port_status(device: UsbDevice, port: int, on: bool):
+    """Sets the power status of a specific port on a USB hub."""
+    device.ctrl_transfer(
+        bmRequestType=CTRL_TYPE_CLASS | CTRL_RECIPIENT_OTHER,
+        bRequest=REQ_SET_FEATURE if on else REQ_CLEAR_FEATURE,
+        wIndex=port,
+        wValue=USB_PORT_FEATURE_POWER,
+    )
+
+
+def _find_device_by_path(sys_path: str) -> Optional[UsbDevice]:
+    """Finds a USB device based on its system path."""
+    bus_num, *port_parts = sys_path.split('-')
+    ports = [int(port) for port in port_parts[0].split('.')]
+    devices = usb.core.find(find_all=True, bus=int(bus_num))
+    if devices:
+        for device in devices:
+            if device.bus == int(bus_num) and list(device.port_numbers) == ports:  # type: ignore
+                return device
+
+    return None
+
+
+def _find_hub_by_device_path(sys_path: str) -> Optional[UsbDevice]:
+    """Finds the USB hub associated with a specific device path."""
+    hub_sys_path = sys_path.rsplit('.', 1)[0]
+    hub_device = _find_device_by_path(hub_sys_path)
+
+    if hub_device is None:
+        return None
+    else:
+        return hub_device if _is_hub(hub_device) else None
+
+
+def _is_hub(device: UsbDevice) -> bool:
+    """Checks if a USB device is a hub"""
+    if device.bDeviceClass == CLASS_HUB:  # type: ignore
+        return True
+    for config in device:
+        for interface in config:
+            if interface.bInterfaceClass == CLASS_HUB:  # type: ignore
+                return True
+    return False
diff --git a/bumble/transport/tcp_server.py b/bumble/transport/tcp_server.py
index 77d0304..0a648fd 100644
--- a/bumble/transport/tcp_server.py
+++ b/bumble/transport/tcp_server.py
@@ -18,6 +18,7 @@
 from __future__ import annotations
 import asyncio
 import logging
+import socket
 
 from .common import Transport, StreamPacketSource
 
@@ -28,6 +29,13 @@ logger = logging.getLogger(__name__)
 
 
 # -----------------------------------------------------------------------------
+
+
+# A pass-through function to ease mock testing.
+async def _create_server(*args, **kw_args):
+    await asyncio.get_running_loop().create_server(*args, **kw_args)
+
+
 async def open_tcp_server_transport(spec: str) -> Transport:
     '''
     Open a TCP server transport.
@@ -38,7 +46,22 @@ async def open_tcp_server_transport(spec: str) -> Transport:
 
     Example: _:9001
     '''
+    local_host, local_port = spec.split(':')
+    return await _open_tcp_server_transport_impl(
+        host=local_host if local_host != '_' else None, port=int(local_port)
+    )
+
 
+async def open_tcp_server_transport_with_socket(sock: socket.socket) -> Transport:
+    '''
+    Open a TCP server transport with an existing socket.
+
+    One reason to use this variant is to let python pick an unused port.
+    '''
+    return await _open_tcp_server_transport_impl(sock=sock)
+
+
+async def _open_tcp_server_transport_impl(**kwargs) -> Transport:
     class TcpServerTransport(Transport):
         async def close(self):
             await super().close()
@@ -77,13 +100,10 @@ async def open_tcp_server_transport(spec: str) -> Transport:
             else:
                 logger.debug('no client, dropping packet')
 
-    local_host, local_port = spec.split(':')
     packet_source = StreamPacketSource()
     packet_sink = TcpServerPacketSink()
-    await asyncio.get_running_loop().create_server(
-        lambda: TcpServerProtocol(packet_source, packet_sink),
-        host=local_host if local_host != '_' else None,
-        port=int(local_port),
+    await _create_server(
+        lambda: TcpServerProtocol(packet_source, packet_sink), **kwargs
     )
 
     return TcpServerTransport(packet_source, packet_sink)
diff --git a/bumble/transport/usb.py b/bumble/transport/usb.py
index 6479016..69e9649 100644
--- a/bumble/transport/usb.py
+++ b/bumble/transport/usb.py
@@ -449,7 +449,7 @@ async def open_usb_transport(spec: str) -> Transport:
         # Look for the first interface with the right class and endpoints
         def find_endpoints(device):
             # pylint: disable-next=too-many-nested-blocks
-            for (configuration_index, configuration) in enumerate(device):
+            for configuration_index, configuration in enumerate(device):
                 interface = None
                 for interface in configuration:
                     setting = None
diff --git a/bumble/utils.py b/bumble/utils.py
index e6aae4d..4c9407f 100644
--- a/bumble/utils.py
+++ b/bumble/utils.py
@@ -117,12 +117,12 @@ class EventWatcher:
         self.handlers = []
 
     @overload
-    def on(self, emitter: EventEmitter, event: str) -> Callable[[_Handler], _Handler]:
-        ...
+    def on(
+        self, emitter: EventEmitter, event: str
+    ) -> Callable[[_Handler], _Handler]: ...
 
     @overload
-    def on(self, emitter: EventEmitter, event: str, handler: _Handler) -> _Handler:
-        ...
+    def on(self, emitter: EventEmitter, event: str, handler: _Handler) -> _Handler: ...
 
     def on(
         self, emitter: EventEmitter, event: str, handler: Optional[_Handler] = None
@@ -144,12 +144,14 @@ class EventWatcher:
         return wrapper if handler is None else wrapper(handler)
 
     @overload
-    def once(self, emitter: EventEmitter, event: str) -> Callable[[_Handler], _Handler]:
-        ...
+    def once(
+        self, emitter: EventEmitter, event: str
+    ) -> Callable[[_Handler], _Handler]: ...
 
     @overload
-    def once(self, emitter: EventEmitter, event: str, handler: _Handler) -> _Handler:
-        ...
+    def once(
+        self, emitter: EventEmitter, event: str, handler: _Handler
+    ) -> _Handler: ...
 
     def once(
         self, emitter: EventEmitter, event: str, handler: Optional[_Handler] = None
diff --git a/examples/async_runner.py b/examples/async_runner.py
index 9e71899..b29a80f 100644
--- a/examples/async_runner.py
+++ b/examples/async_runner.py
@@ -25,6 +25,7 @@ from bumble.utils import AsyncRunner
 my_work_queue1 = AsyncRunner.WorkQueue()
 my_work_queue2 = AsyncRunner.WorkQueue(create_task=False)
 
+
 # -----------------------------------------------------------------------------
 @AsyncRunner.run_in_task()
 async def func1(x, y):
@@ -60,7 +61,7 @@ async def func4(x, y):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     print("MAIN: start, loop=", asyncio.get_running_loop())
     print("MAIN: invoke func1")
     func1(1, 2)
diff --git a/examples/battery_client.py b/examples/battery_client.py
index 3cf11b4..e9105db 100644
--- a/examples/battery_client.py
+++ b/examples/battery_client.py
@@ -21,23 +21,29 @@ import os
 import logging
 from bumble.colors import color
 from bumble.device import Device
+from bumble.hci import Address
 from bumble.transport import open_transport
 from bumble.profiles.battery_service import BatteryServiceProxy
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: battery_client.py <transport-spec> <bluetooth-address>')
         print('example: battery_client.py usb:0 E1:CA:72:48:C4:E8')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport(sys.argv[1]) as hci_transport:
         print('<<< connected')
 
         # Create and start a device
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
         await device.power_on()
 
         # Connect to the peer
diff --git a/examples/battery_server.py b/examples/battery_server.py
index b7f941f..f509954 100644
--- a/examples/battery_server.py
+++ b/examples/battery_server.py
@@ -29,14 +29,16 @@ from bumble.profiles.battery_service import BatteryService
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: python battery_server.py <device-config> <transport-spec>')
         print('example: python battery_server.py device1.json usb:0')
         return
 
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         # Add a Battery Service to the GATT sever
         battery_service = BatteryService(lambda _: random.randint(0, 100))
diff --git a/examples/device_information_client.py b/examples/device_information_client.py
index 416aa2f..f6d51ba 100644
--- a/examples/device_information_client.py
+++ b/examples/device_information_client.py
@@ -21,12 +21,13 @@ import os
 import logging
 from bumble.colors import color
 from bumble.device import Device, Peer
+from bumble.hci import Address
 from bumble.profiles.device_information_service import DeviceInformationServiceProxy
 from bumble.transport import open_transport
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print(
             'Usage: device_information_client.py <transport-spec> <bluetooth-address>'
@@ -35,11 +36,16 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport(sys.argv[1]) as hci_transport:
         print('<<< connected')
 
         # Create and start a device
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
         await device.power_on()
 
         # Connect to the peer
diff --git a/examples/device_information_server.py b/examples/device_information_server.py
index d437cae..92474bc 100644
--- a/examples/device_information_server.py
+++ b/examples/device_information_server.py
@@ -28,14 +28,16 @@ from bumble.profiles.device_information_service import DeviceInformationService
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: python device_info_server.py <device-config> <transport-spec>')
         print('example: python device_info_server.py device1.json usb:0')
         return
 
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         # Add a Device Information Service to the GATT sever
         device_information_service = DeviceInformationService(
@@ -64,7 +66,7 @@ async def main():
         # Go!
         await device.power_on()
         await device.start_advertising(auto_restart=True)
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/heart_rate_client.py b/examples/heart_rate_client.py
index ecfcffb..ea7bc36 100644
--- a/examples/heart_rate_client.py
+++ b/examples/heart_rate_client.py
@@ -21,23 +21,29 @@ import os
 import logging
 from bumble.colors import color
 from bumble.device import Device
+from bumble.hci import Address
 from bumble.transport import open_transport
 from bumble.profiles.heart_rate_service import HeartRateServiceProxy
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: heart_rate_client.py <transport-spec> <bluetooth-address>')
         print('example: heart_rate_client.py usb:0 E1:CA:72:48:C4:E8')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport(sys.argv[1]) as hci_transport:
         print('<<< connected')
 
         # Create and start a device
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
         await device.power_on()
 
         # Connect to the peer
diff --git a/examples/heart_rate_server.py b/examples/heart_rate_server.py
index fad809f..e40d5db 100644
--- a/examples/heart_rate_server.py
+++ b/examples/heart_rate_server.py
@@ -33,14 +33,16 @@ from bumble.utils import AsyncRunner
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: python heart_rate_server.py <device-config> <transport-spec>')
         print('example: python heart_rate_server.py device1.json usb:0')
         return
 
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         # Keep track of accumulated expended energy
         energy_start_time = time.time()
diff --git a/examples/hfp_gateway.html b/examples/hfp_gateway.html
new file mode 100644
index 0000000..1559c43
--- /dev/null
+++ b/examples/hfp_gateway.html
@@ -0,0 +1,350 @@
+<html data-bs-theme="dark">
+
+<head>
+    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet"
+        integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous">
+    <script src="https://unpkg.com/pcm-player"></script>
+</head>
+
+<body>
+    <nav class="navbar navbar-dark bg-primary">
+        <div class="container">
+            <span class="navbar-brand mb-0 h1">Bumble HFP Audio Gateway</span>
+        </div>
+    </nav>
+    <br>
+
+    <div class="container">
+
+        <label class="form-label">Send AT Response</label>
+        <div class="input-group mb-3">
+            <input type="text" class="form-control" placeholder="AT Response" aria-label="AT response" id="at_response">
+            <button class="btn btn-primary" type="button"
+                onclick="send_at_response(document.getElementById('at_response').value)">Send</button>
+        </div>
+
+        <div class="row">
+            <div class="col-3">
+                <label class="form-label">Speaker Volume</label>
+                <div class="input-group mb-3 col-auto">
+                    <input type="text" class="form-control" placeholder="0 - 15" aria-label="Speaker Volume"
+                        id="speaker_volume">
+                    <button class="btn btn-primary" type="button"
+                        onclick="send_at_response(`+VGS: ${document.getElementById('speaker_volume').value}`)">Set</button>
+                </div>
+            </div>
+            <div class="col-3">
+                <label class="form-label">Mic Volume</label>
+                <div class="input-group mb-3 col-auto">
+                    <input type="text" class="form-control" placeholder="0 - 15" aria-label="Mic Volume"
+                        id="mic_volume">
+                    <button class="btn btn-primary" type="button"
+                        onclick="send_at_response(`+VGM: ${document.getElementById('mic_volume').value}`)">Set</button>
+                </div>
+            </div>
+            <div class="col-3">
+                <label class="form-label">Browser Gain</label>
+                <input type="range" class="form-range" id="browser-gain" min="0" max="2" value="1" step="0.1" onchange="setGain()">
+            </div>
+        </div>
+
+        <div class="row">
+            <div class="col-auto">
+                <div class="input-group mb-3">
+                    <span class="input-group-text">Codec</span>
+
+                    <select class="form-select" id="codec">
+                        <option selected value="1">CVSD</option>
+                        <option value="2">MSBC</option>
+                    </select>
+                </div>
+            </div>
+
+            <div class="col-auto">
+                <button class="btn btn-primary" onclick="negotiate_codec()">Negotiate Codec</button>
+            </div>
+            <div class="col-auto">
+                <button class="btn btn-primary" onclick="connect_sco()">Connect SCO</button>
+            </div>
+            <div class="col-auto">
+                <button class="btn btn-primary" onclick="disconnect_sco()">Disconnect SCO</button>
+            </div>
+            <div class="col-auto">
+                <button class="btn btn-danger" onclick="connectAudio()">Connect Audio</button>
+            </div>
+        </div>
+
+        <hr>
+
+        <div class="row">
+            <h4>AG Indicators</h2>
+                <div class="col-3">
+                    <label class="form-label">call</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="call">
+                            <option selected value="0">Inactive</option>
+                            <option value="1">Active</option>
+                        </select>
+                        <button class="btn btn-primary" type="button" onclick="update_ag_indicator('call')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">callsetup</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="callsetup">
+                            <option selected value="0">Idle</option>
+                            <option value="1">Incoming</option>
+                            <option value="2">Outgoing</option>
+                            <option value="3">Remote Alerted</option>
+                        </select>
+                        <button class="btn btn-primary" type="button"
+                            onclick="update_ag_indicator('callsetup')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">callheld</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="callsetup">
+                            <option selected value="0">0</option>
+                            <option value="1">1</option>
+                            <option value="2">2</option>
+                        </select>
+                        <button class="btn btn-primary" type="button"
+                            onclick="update_ag_indicator('callheld')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">signal</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="signal">
+                            <option selected value="0">0</option>
+                            <option value="1">1</option>
+                            <option value="2">2</option>
+                            <option value="3">3</option>
+                            <option value="4">4</option>
+                            <option value="5">5</option>
+                        </select>
+                        <button class="btn btn-primary" type="button"
+                            onclick="update_ag_indicator('signal')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">roam</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="roam">
+                            <option selected value="0">0</option>
+                            <option value="1">1</option>
+                        </select>
+                        <button class="btn btn-primary" type="button" onclick="update_ag_indicator('roam')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">battchg</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="battchg">
+                            <option selected value="0">0</option>
+                            <option value="1">1</option>
+                            <option value="2">2</option>
+                            <option value="3">3</option>
+                            <option value="4">4</option>
+                            <option value="5">5</option>
+                        </select>
+                        <button class="btn btn-primary" type="button"
+                            onclick="update_ag_indicator('battchg')">Set</button>
+                    </div>
+                </div>
+                <div class="col-3">
+                    <label class="form-label">service</label>
+                    <div class="input-group mb-3 col-auto">
+                        <select class="form-select" id="service">
+                            <option selected value="0">0</option>
+                            <option value="1">1</option>
+                        </select>
+                        <button class="btn btn-primary" type="button"
+                            onclick="update_ag_indicator('service')">Set</button>
+                    </div>
+                </div>
+        </div>
+
+        <hr>
+
+        <button class="btn btn-primary" onclick="send_at_response('+BVRA: 1')">Start Voice Assistant</button>
+        <button class="btn btn-primary" onclick="send_at_response('+BVRA: 0')">Stop Voice Assistant</button>
+
+        <hr>
+
+
+        <h4>Calls</h4>
+        <div id="call-lists">
+            <template id="call-template">
+                <div class="row call-row">
+                    <div class="input-group mb-3">
+                        <label class="input-group-text">Index</label>
+                        <input class="form-control call-index" value="1">
+
+                        <label class="input-group-text">Number</label>
+                        <input class="form-control call-number">
+
+                        <label class="input-group-text">Direction</label>
+                        <select class="form-select call-direction">
+                            <option selected value="0">Originated</option>
+                            <option value="1">Terminated</option>
+                        </select>
+
+                        <label class="input-group-text">Status</label>
+                        <select class="form-select call-status">
+                            <option value="0">ACTIVE</option>
+                            <option value="1">HELD</option>
+                            <option value="2">DIALING</option>
+                            <option value="3">ALERTING</option>
+                            <option value="4">INCOMING</option>
+                            <option value="5">WAITING</option>
+                        </select>
+                        <button class="btn btn-primary call-remover">❌</button>
+                    </div>
+                </div>
+            </template>
+        </div>
+
+        <button class="btn btn-primary" onclick="add_call()">➕ Add Call</button>
+        <button class="btn btn-primary" onclick="update_calls()">🗘 Update Calls</button>
+
+        <hr>
+
+        <div id="socketStateContainer" class="bg-body-tertiary p-3 rounded-2">
+            <h3>Log</h3>
+            <code id="log" style="white-space: pre-line;"></code>
+        </div>
+    </div>
+
+
+    <script>
+        let atResponseInput = document.getElementById("at_response")
+        let gainInput = document.getElementById('browser-gain')
+        let log = document.getElementById("log")
+        let socket = new WebSocket('ws://localhost:8888');
+        let sampleRate = 0;
+        let player;
+
+        socket.binaryType = "arraybuffer";
+        socket.onopen = _ => {
+            log.textContent += 'SOCKET OPEN\n'
+        }
+        socket.onclose = _ => {
+            log.textContent += 'SOCKET CLOSED\n'
+        }
+        socket.onerror = (error) => {
+            log.textContent += 'SOCKET ERROR\n'
+            console.log(`ERROR: ${error}`)
+        }
+        socket.onmessage = function (message) {
+            if (typeof message.data === 'string' || message.data instanceof String) {
+                log.textContent += `<-- ${event.data}\n`
+                const jsonMessage = JSON.parse(event.data)
+
+                if (jsonMessage.type == 'speaker_volume') {
+                    document.getElementById('speaker_volume').value = jsonMessage.level;
+                } else if (jsonMessage.type == 'microphone_volume') {
+                    document.getElementById('microphone_volume').value = jsonMessage.level;
+                } else if (jsonMessage.type == 'sco_state_change') {
+                    sampleRate = jsonMessage.sample_rate;
+                    console.log(sampleRate);
+                    if (player != null) {
+                        player = new PCMPlayer({
+                            inputCodec: 'Int16',
+                            channels: 1,
+                            sampleRate: sampleRate,
+                            flushTime: 7.5,
+                        });
+                        player.volume(gainInput.value);
+                    }
+                }
+            } else {
+                // BINARY audio data.
+                if (player == null) return;
+                player.feed(message.data);
+            }
+        };
+
+        function send(message) {
+            if (socket && socket.readyState == WebSocket.OPEN) {
+                let jsonMessage = JSON.stringify(message)
+                log.textContent += `--> ${jsonMessage}\n`
+                socket.send(jsonMessage)
+            } else {
+                log.textContent += 'NOT CONNECTED\n'
+            }
+        }
+
+        function send_at_response(response) {
+            send({ type: 'at_response', response: response })
+        }
+
+        function update_ag_indicator(indicator) {
+            const value = document.getElementById(indicator).value
+            send({ type: 'ag_indicator', indicator: indicator, value: value })
+        }
+
+        function connect_sco() {
+            send({ type: 'connect_sco' })
+        }
+
+        function negotiate_codec() {
+            const codec = document.getElementById('codec').value
+            send({ type: 'negotiate_codec', codec: codec })
+        }
+
+        function disconnect_sco() {
+            send({ type: 'disconnect_sco' })
+        }
+
+        function add_call() {
+            let callLists = document.getElementById('call-lists');
+            let template = document.getElementById('call-template');
+
+            let newNode = document.importNode(template.content, true);
+            newNode.querySelector('.call-remover').onclick = function (event) {
+                event.target.closest('.call-row').remove();
+            }
+            callLists.appendChild(newNode);
+        }
+
+        function update_calls() {
+            let callLists = document.getElementById('call-lists');
+            send({
+                type: 'update_calls',
+                calls: Array.from(
+                    callLists.querySelectorAll('.call-row')).map(
+                        function (element) {
+                            return {
+                                index: element.querySelector('.call-index').value,
+                                number: element.querySelector('.call-number').value,
+                                direction: element.querySelector('.call-direction').value,
+                                status: element.querySelector('.call-status').value,
+                            }
+                        }
+                    ),
+            }
+            )
+        }
+
+        function connectAudio() {
+            player = new PCMPlayer({
+                inputCodec: 'Int16',
+                channels: 1,
+                sampleRate: sampleRate,
+                flushTime: 7.5,
+            });
+            player.volume(gainInput.value);
+        }
+
+        function setGain() {
+            if (player != null) {
+                player.volume(gainInput.value);
+            }
+        }
+    </script>
+    </div>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/examples/hfp_gateway.json b/examples/hfp_gateway.json
index 5e3d72b..67bb278 100644
--- a/examples/hfp_gateway.json
+++ b/examples/hfp_gateway.json
@@ -1,4 +1,5 @@
 {
     "name": "Bumble Phone",
-    "class_of_device": 6291980
+    "class_of_device": 6291980,
+    "keystore": "JsonKeyStore"
 }
diff --git a/examples/hfp_handsfree.html b/examples/hfp_handsfree.html
index a86fc4a..30be04e 100644
--- a/examples/hfp_handsfree.html
+++ b/examples/hfp_handsfree.html
@@ -1,79 +1,132 @@
-<html>
-    <head>
-        <style>
-* {
-    font-family: sans-serif;
-}
-
-label {
-    display: block;
-}
-
-input, label {
-    margin: .4rem 0;
-}
-        </style>
-    </head>
-    <body>
-        Server Port <input id="port" type="text" value="8989"></input> <button onclick="connect()">Connect</button><br>
-        AT Command <input type="text" id="at_command" required size="10"> <button onclick="send_at_command()">Send</button><br>
-        Dial Phone Number <input type="text" id="dial_number" required size="10"> <button onclick="dial()">Dial</button><br>
-        <button onclick="answer()">Answer</button>
-        <button onclick="hangup()">Hang Up</button>
-        <button onclick="start_voice_assistant()">Start Voice Assistant</button>
-        <button onclick="stop_voice_assistant()">Stop Voice Assistant</button>
+<html data-bs-theme="dark">
+
+<head>
+    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet"
+        integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous">
+</head>
+
+<body>
+    <nav class="navbar navbar-dark bg-primary">
+        <div class="container">
+            <span class="navbar-brand mb-0 h1">Bumble Handsfree</span>
+        </div>
+    </nav>
+    <br>
+
+    <div class="container">
+
+        <label class="form-label">Server Port</label>
+        <div class="input-group mb-3">
+            <input type="text" class="form-control" aria-label="Port Number" value="8989" id="port">
+            <button class="btn btn-primary" type="button" onclick="connect()">Connect</button>
+        </div>
+
+        <label class="form-label">Dial Phone Number</label>
+        <div class="input-group mb-3">
+            <input type="text" class="form-control" placeholder="Phone Number" aria-label="Phone Number"
+                id="dial_number">
+            <button class="btn btn-primary" type="button"
+                onclick="send_at_command(`ATD${dialNumberInput.value}`)">Dial</button>
+        </div>
+
+        <label class="form-label">Send AT Command</label>
+        <div class="input-group mb-3">
+            <input type="text" class="form-control" placeholder="AT Command" aria-label="AT command" id="at_command">
+            <button class="btn btn-primary" type="button"
+                onclick="send_at_command(document.getElementById('at_command').value)">Send</button>
+        </div>
+
+        <div class="row">
+            <div class="col-auto">
+                <label class="form-label">Battery Level</label>
+                <div class="input-group mb-3">
+                    <input type="text" class="form-control" placeholder="0 - 100" aria-label="Battery Level"
+                        id="battery_level">
+                    <button class="btn btn-primary" type="button"
+                        onclick="send_at_command(`AT+BIEV=2,${document.getElementById('battery_level').value}`)">Set</button>
+                </div>
+            </div>
+            <div class="col-auto">
+                <label class="form-label">Speaker Volume</label>
+                <div class="input-group mb-3 col-auto">
+                    <input type="text" class="form-control" placeholder="0 - 15" aria-label="Speaker Volume"
+                        id="speaker_volume">
+                    <button class="btn btn-primary" type="button"
+                        onclick="send_at_command(`AT+VGS=${document.getElementById('speaker_volume').value}`)">Set</button>
+                </div>
+            </div>
+            <div class="col-auto">
+                <label class="form-label">Mic Volume</label>
+                <div class="input-group mb-3 col-auto">
+                    <input type="text" class="form-control" placeholder="0 - 15" aria-label="Mic Volume"
+                        id="mic_volume">
+                    <button class="btn btn-primary" type="button"
+                        onclick="send_at_command(`AT+VGM=${document.getElementById('mic_volume').value}`)">Set</button>
+                </div>
+            </div>
+        </div>
+
+        <button class="btn btn-primary" onclick="send_at_command('ATA')">Answer</button>
+        <button class="btn btn-primary" onclick="send_at_command('AT+CHUP')">Hang Up</button>
+        <button class="btn btn-primary" onclick="send_at_command('AT+BLDN')">Redial</button>
+        <button class="btn btn-primary" onclick="send({ type: 'query_call'})">Get Call Status</button>
+
+        <br><br>
+
+        <button class="btn btn-primary" onclick="send_at_command('AT+BVRA=1')">Start Voice Assistant</button>
+        <button class="btn btn-primary" onclick="send_at_command('AT+BVRA=0')">Stop Voice Assistant</button>
+
         <hr>
-        <div id="socketState"></div>
-        <script>
+
+        <div id="socketStateContainer" class="bg-body-tertiary p-3 rounded-2">
+            <h3>Log</h3>
+            <code id="log" style="white-space: pre-line;"></code>
+        </div>
+    </div>
+
+
+    <script>
         let portInput = document.getElementById("port")
         let atCommandInput = document.getElementById("at_command")
-        let dialNumberInput = document.getElementById("dial_number")
-        let socketState = document.getElementById("socketState")
+        let log = document.getElementById("log")
         let socket
 
         function connect() {
             socket = new WebSocket(`ws://localhost:${portInput.value}`);
             socket.onopen = _ => {
-                socketState.innerText = 'OPEN'
+                log.textContent += 'OPEN\n'
             }
             socket.onclose = _ => {
-                socketState.innerText = 'CLOSED'
+                log.textContent += 'CLOSED\n'
             }
             socket.onerror = (error) => {
-                socketState.innerText = 'ERROR'
+                log.textContent += 'ERROR\n'
                 console.log(`ERROR: ${error}`)
             }
+            socket.onmessage = (event) => {
+                log.textContent += `<-- ${event.data}\n`
+                let volume_state = JSON.parse(event.data)
+                volumeSetting.value = volume_state.volume_setting
+                changeCounter.value = volume_state.change_counter
+                muted.checked = volume_state.muted ? true : false
+            }
         }
 
         function send(message) {
             if (socket && socket.readyState == WebSocket.OPEN) {
-                socket.send(JSON.stringify(message))
+                let jsonMessage = JSON.stringify(message)
+                log.textContent += `--> ${jsonMessage}\n`
+                socket.send(jsonMessage)
+            } else {
+                log.textContent += 'NOT CONNECTED\n'
             }
         }
 
-        function send_at_command() {
-            send({ type:'at_command', command: atCommandInput.value })
-        }
-
-        function answer() {
-            send({ type:'at_command', command: 'ATA' })
-        }
-
-        function hangup() {
-            send({ type:'at_command', command: 'AT+CHUP' })
-        }
-
-        function dial() {
-            send({ type:'at_command', command: `ATD${dialNumberInput.value}` })
+        function send_at_command(command) {
+            send({ type: 'at_command', 'command': command })
         }
+    </script>
+    </div>
+</body>
 
-        function start_voice_assistant() {
-            send(({ type:'at_command', command: 'AT+BVRA=1' }))
-        }
-
-        function stop_voice_assistant() {
-            send(({ type:'at_command', command: 'AT+BVRA=0' }))
-        }
-</script>
-    </body>
-</html>
+</html>
\ No newline at end of file
diff --git a/examples/keyboard.py b/examples/keyboard.py
index 314a805..f2afe18 100644
--- a/examples/keyboard.py
+++ b/examples/keyboard.py
@@ -416,7 +416,7 @@ async def keyboard_device(device, command):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print(
             'Usage: python keyboard.py <device-config> <transport-spec> <command>'
@@ -434,9 +434,11 @@ async def main():
         )
         return
 
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         # Create a device to manage the host
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         command = sys.argv[3]
         if command == 'connect':
diff --git a/examples/run_a2dp_info.py b/examples/run_a2dp_info.py
index 3a35695..e05c87e 100644
--- a/examples/run_a2dp_info.py
+++ b/examples/run_a2dp_info.py
@@ -139,18 +139,20 @@ async def find_a2dp_service(connection):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print('Usage: run_a2dp_info.py <device-config> <transport-spec> <bt-addr>')
         print('example: run_a2dp_info.py classic1.json usb:0 14:7D:DA:4E:53:A8')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Start the controller
@@ -187,7 +189,7 @@ async def main():
         client = await AVDTP_Protocol.connect(connection, avdtp_version)
 
         # Discover all endpoints on the remote device
-        endpoints = await client.discover_remote_endpoints()
+        endpoints = list(await client.discover_remote_endpoints())
         print(f'@@@ Found {len(endpoints)} endpoints')
         for endpoint in endpoints:
             print('@@@', endpoint)
diff --git a/examples/run_a2dp_sink.py b/examples/run_a2dp_sink.py
index 61bdce3..ca1af84 100644
--- a/examples/run_a2dp_sink.py
+++ b/examples/run_a2dp_sink.py
@@ -19,6 +19,7 @@ import asyncio
 import sys
 import os
 import logging
+from typing import Any, Dict
 
 from bumble.device import Device
 from bumble.transport import open_transport_or_link
@@ -41,7 +42,7 @@ from bumble.a2dp import (
     SbcMediaCodecInformation,
 )
 
-Context = {'output': None}
+Context: Dict[Any, Any] = {'output': None}
 
 
 # -----------------------------------------------------------------------------
@@ -104,7 +105,7 @@ def on_rtp_packet(packet):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print(
             'Usage: run_a2dp_sink.py <device-config> <transport-spec> <sbc-file> '
@@ -114,14 +115,16 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         with open(sys.argv[3], 'wb') as sbc_file:
             Context['output'] = sbc_file
 
             # Create a device
-            device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+            device = Device.from_config_file_with_hci(
+                sys.argv[1], hci_transport.source, hci_transport.sink
+            )
             device.classic_enabled = True
 
             # Setup the SDP to expose the sink service
@@ -162,7 +165,7 @@ async def main():
                 await device.set_discoverable(True)
                 await device.set_connectable(True)
 
-            await hci_source.wait_for_termination()
+            await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_a2dp_source.py b/examples/run_a2dp_source.py
index 4645229..a1f955b 100644
--- a/examples/run_a2dp_source.py
+++ b/examples/run_a2dp_source.py
@@ -114,7 +114,7 @@ async def stream_packets(read_function, protocol):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print(
             'Usage: run_a2dp_source.py <device-config> <transport-spec> <sbc-file> '
@@ -126,11 +126,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Setup the SDP to expose the SRC service
@@ -186,7 +188,7 @@ async def main():
                 await device.set_discoverable(True)
                 await device.set_connectable(True)
 
-            await hci_source.wait_for_termination()
+            await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_advertiser.py b/examples/run_advertiser.py
index fb59426..4c67d10 100644
--- a/examples/run_advertiser.py
+++ b/examples/run_advertiser.py
@@ -28,7 +28,7 @@ from bumble.transport import open_transport_or_link
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_advertiser.py <config-file> <transport-spec> [type] [address]'
@@ -50,10 +50,12 @@ async def main():
         target = None
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         if advertising_type.is_scannable:
             device.scan_response_data = bytes(
@@ -66,7 +68,7 @@ async def main():
 
         await device.power_on()
         await device.start_advertising(advertising_type=advertising_type, target=target)
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_asha_sink.py b/examples/run_asha_sink.py
index 2d6f0d5..105eb75 100644
--- a/examples/run_asha_sink.py
+++ b/examples/run_asha_sink.py
@@ -49,7 +49,7 @@ ASHA_LE_PSM_OUT_CHARACTERISTIC = UUID(
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 4:
         print(
             'Usage: python run_asha_sink.py <device-config> <transport-spec> '
@@ -60,8 +60,10 @@ async def main():
 
     audio_out = open(sys.argv[3], 'wb')
 
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
 
         # Handler for audio control commands
         def on_audio_control_point_write(_connection, value):
@@ -197,7 +199,7 @@ async def main():
         await device.power_on()
         await device.start_advertising(auto_restart=True)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_avrcp.py b/examples/run_avrcp.py
index 4bb4143..793e000 100644
--- a/examples/run_avrcp.py
+++ b/examples/run_avrcp.py
@@ -331,7 +331,7 @@ class Delegate(avrcp.Delegate):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_avrcp_controller.py <device-config> <transport-spec> '
@@ -341,11 +341,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Setup the SDP to expose the sink service
diff --git a/examples/run_classic_connect.py b/examples/run_classic_connect.py
index 0acaedd..362e6b8 100644
--- a/examples/run_classic_connect.py
+++ b/examples/run_classic_connect.py
@@ -32,7 +32,7 @@ from bumble.sdp import (
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_classic_connect.py <device-config> <transport-spec> '
@@ -42,11 +42,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
         device.le_enabled = False
         await device.power_on()
diff --git a/examples/run_classic_discoverable.py b/examples/run_classic_discoverable.py
index 076a9ec..52f47fc 100644
--- a/examples/run_classic_discoverable.py
+++ b/examples/run_classic_discoverable.py
@@ -91,18 +91,20 @@ SDP_SERVICE_RECORDS = {
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print('Usage: run_classic_discoverable.py <device-config> <transport-spec>')
         print('example: run_classic_discoverable.py classic1.json usb:04b4:f901')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
         device.sdp_service_records = SDP_SERVICE_RECORDS
         await device.power_on()
@@ -111,7 +113,7 @@ async def main():
         await device.set_discoverable(True)
         await device.set_connectable(True)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_classic_discovery.py b/examples/run_classic_discovery.py
index 569c8b3..af35bb7 100644
--- a/examples/run_classic_discovery.py
+++ b/examples/run_classic_discovery.py
@@ -20,8 +20,8 @@ import sys
 import os
 import logging
 from bumble.colors import color
-
 from bumble.device import Device
+from bumble.hci import Address
 from bumble.transport import open_transport_or_link
 from bumble.core import DeviceClass
 
@@ -53,22 +53,27 @@ class DiscoveryListener(Device.Listener):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 2:
         print('Usage: run_classic_discovery.py <transport-spec>')
         print('example: run_classic_discovery.py usb:04b4:f901')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[1]) as hci_transport:
         print('<<< connected')
 
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
         device.listener = DiscoveryListener()
         await device.power_on()
         await device.start_discovery()
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_connect_and_encrypt.py b/examples/run_connect_and_encrypt.py
index b541a0e..3b9d180 100644
--- a/examples/run_connect_and_encrypt.py
+++ b/examples/run_connect_and_encrypt.py
@@ -25,7 +25,7 @@ from bumble.transport import open_transport_or_link
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_connect_and_encrypt.py <device-config> <transport-spec> '
@@ -37,11 +37,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         await device.power_on()
 
         # Connect to the peer
@@ -56,7 +58,7 @@ async def main():
             print(f'!!! Encryption failed: {error}')
             return
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_controller.py b/examples/run_controller.py
index 596ac8b..05dedfc 100644
--- a/examples/run_controller.py
+++ b/examples/run_controller.py
@@ -36,7 +36,7 @@ from bumble.transport import open_transport_or_link
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 4:
         print(
             'Usage: run_controller.py <controller-address> <device-config> '
@@ -49,7 +49,7 @@ async def main():
         return
 
     print('>>> connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[3]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[3]) as hci_transport:
         print('>>> connected')
 
         # Create a local link
@@ -57,7 +57,10 @@ async def main():
 
         # Create a first controller using the packet source/sink as its host interface
         controller1 = Controller(
-            'C1', host_source=hci_source, host_sink=hci_sink, link=link
+            'C1',
+            host_source=hci_transport.source,
+            host_sink=hci_transport.sink,
+            link=link,
         )
         controller1.random_address = sys.argv[1]
 
@@ -98,7 +101,7 @@ async def main():
         await device.start_advertising()
         await device.start_scanning()
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_controller_with_scanner.py b/examples/run_controller_with_scanner.py
index 9603cff..9e935a9 100644
--- a/examples/run_controller_with_scanner.py
+++ b/examples/run_controller_with_scanner.py
@@ -20,9 +20,9 @@ import asyncio
 import sys
 import os
 from bumble.colors import color
-
 from bumble.device import Device
 from bumble.controller import Controller
+from bumble.hci import Address
 from bumble.link import LocalLink
 from bumble.transport import open_transport_or_link
 
@@ -45,14 +45,14 @@ class ScannerListener(Device.Listener):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 2:
         print('Usage: run_controller.py <transport-spec>')
         print('example: run_controller_with_scanner.py serial:/dev/pts/14,1000000')
         return
 
     print('>>> connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[1]) as hci_transport:
         print('>>> connected')
 
         # Create a local link
@@ -60,22 +60,25 @@ async def main():
 
         # Create a first controller using the packet source/sink as its host interface
         controller1 = Controller(
-            'C1', host_source=hci_source, host_sink=hci_sink, link=link
+            'C1',
+            host_source=hci_transport.source,
+            host_sink=hci_transport.sink,
+            link=link,
+            public_address='E0:E1:E2:E3:E4:E5',
         )
-        controller1.address = 'E0:E1:E2:E3:E4:E5'
 
         # Create a second controller using the same link
         controller2 = Controller('C2', link=link)
 
         # Create a device with a scanner listener
         device = Device.with_hci(
-            'Bumble', 'F0:F1:F2:F3:F4:F5', controller2, controller2
+            'Bumble', Address('F0:F1:F2:F3:F4:F5'), controller2, controller2
         )
         device.listener = ScannerListener()
         await device.power_on()
         await device.start_scanning()
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_device_with_snooper.py b/examples/run_device_with_snooper.py
index 69a187f..87307e8 100644
--- a/examples/run_device_with_snooper.py
+++ b/examples/run_device_with_snooper.py
@@ -20,30 +20,36 @@ import sys
 import os
 import logging
 from bumble.colors import color
-
+from bumble.hci import Address
 from bumble.device import Device
 from bumble.transport import open_transport_or_link
 from bumble.snoop import BtSnooper
 
+
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) != 3:
         print('Usage: run_device_with_snooper.py <transport-spec> <snoop-file>')
         print('example: run_device_with_snooper.py usb:0 btsnoop.log')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[1]) as hci_transport:
         print('<<< connected')
 
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
 
         with open(sys.argv[2], "wb") as snoop_file:
             device.host.snooper = BtSnooper(snoop_file)
             await device.power_on()
             await device.start_scanning()
 
-            await hci_source.wait_for_termination()
+            await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_gatt_client.py b/examples/run_gatt_client.py
index dcf8a1b..4548159 100644
--- a/examples/run_gatt_client.py
+++ b/examples/run_gatt_client.py
@@ -69,7 +69,7 @@ class Listener(Device.Listener):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_gatt_client.py <device-config> <transport-spec> '
@@ -79,11 +79,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device to manage the host, with a custom listener
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.listener = Listener(device)
         await device.power_on()
 
diff --git a/examples/run_gatt_client_and_server.py b/examples/run_gatt_client_and_server.py
index 609fe18..e25d14c 100644
--- a/examples/run_gatt_client_and_server.py
+++ b/examples/run_gatt_client_and_server.py
@@ -19,21 +19,21 @@ import asyncio
 import os
 import logging
 from bumble.colors import color
-
 from bumble.core import ProtocolError
 from bumble.controller import Controller
 from bumble.device import Device, Peer
+from bumble.hci import Address
 from bumble.host import Host
 from bumble.link import LocalLink
 from bumble.gatt import (
     Service,
     Characteristic,
     Descriptor,
-    show_services,
     GATT_CHARACTERISTIC_USER_DESCRIPTION_DESCRIPTOR,
     GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC,
     GATT_DEVICE_INFORMATION_SERVICE,
 )
+from bumble.gatt_client import show_services
 
 
 # -----------------------------------------------------------------------------
@@ -43,7 +43,7 @@ class ServerListener(Device.Listener):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     # Create a local link
     link = LocalLink()
 
@@ -51,14 +51,18 @@ async def main():
     client_controller = Controller("client controller", link=link)
     client_host = Host()
     client_host.controller = client_controller
-    client_device = Device("client", address='F0:F1:F2:F3:F4:F5', host=client_host)
+    client_device = Device(
+        "client", address=Address('F0:F1:F2:F3:F4:F5'), host=client_host
+    )
     await client_device.power_on()
 
     # Setup a stack for the server
     server_controller = Controller("server controller", link=link)
     server_host = Host()
     server_host.controller = server_controller
-    server_device = Device("server", address='F6:F7:F8:F9:FA:FB', host=server_host)
+    server_device = Device(
+        "server", address=Address('F6:F7:F8:F9:FA:FB'), host=server_host
+    )
     server_device.listener = ServerListener()
     await server_device.power_on()
 
diff --git a/examples/run_gatt_server.py b/examples/run_gatt_server.py
index 46d42a2..874115c 100644
--- a/examples/run_gatt_server.py
+++ b/examples/run_gatt_server.py
@@ -71,7 +71,7 @@ def my_custom_write_with_error(connection, value):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: run_gatt_server.py <device-config> <transport-spec> '
@@ -81,11 +81,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device to manage the host
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.listener = Listener(device)
 
         # Add a few entries to the device's GATT server
@@ -146,7 +148,7 @@ async def main():
         else:
             await device.start_advertising(auto_restart=True)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_hfp_gateway.py b/examples/run_hfp_gateway.py
index c3b392d..851f97c 100644
--- a/examples/run_hfp_gateway.py
+++ b/examples/run_hfp_gateway.py
@@ -16,240 +16,270 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import json
 import sys
 import os
+import io
 import logging
+import websockets
 
-from bumble.colors import color
+from typing import Optional
 
 import bumble.core
-from bumble.device import Device
+from bumble.device import Device, ScoLink
 from bumble.transport import open_transport_or_link
 from bumble.core import (
-    BT_HANDSFREE_SERVICE,
-    BT_RFCOMM_PROTOCOL_ID,
     BT_BR_EDR_TRANSPORT,
 )
-from bumble import rfcomm, hfp
-from bumble.hci import HCI_SynchronousDataPacket
-from bumble.sdp import (
-    Client as SDP_Client,
-    DataElement,
-    ServiceAttribute,
-    SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-    SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
-    SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-)
+from bumble import hci, rfcomm, hfp
 
 
 logger = logging.getLogger(__name__)
 
+ws: Optional[websockets.WebSocketServerProtocol] = None
+ag_protocol: Optional[hfp.AgProtocol] = None
+source_file: Optional[io.BufferedReader] = None
 
-# -----------------------------------------------------------------------------
-# pylint: disable-next=too-many-nested-blocks
-async def list_rfcomm_channels(device, connection):
-    # Connect to the SDP Server
-    sdp_client = SDP_Client(connection)
-    await sdp_client.connect()
-
-    # Search for services that support the Handsfree Profile
-    search_result = await sdp_client.search_attributes(
-        [BT_HANDSFREE_SERVICE],
-        [
-            SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-            SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-            SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID,
+
+def _default_configuration() -> hfp.AgConfiguration:
+    return hfp.AgConfiguration(
+        supported_ag_features=[
+            hfp.AgFeature.HF_INDICATORS,
+            hfp.AgFeature.IN_BAND_RING_TONE_CAPABILITY,
+            hfp.AgFeature.REJECT_CALL,
+            hfp.AgFeature.CODEC_NEGOTIATION,
+            hfp.AgFeature.ESCO_S4_SETTINGS_SUPPORTED,
+            hfp.AgFeature.ENHANCED_CALL_STATUS,
         ],
+        supported_ag_indicators=[
+            hfp.AgIndicatorState.call(),
+            hfp.AgIndicatorState.callsetup(),
+            hfp.AgIndicatorState.callheld(),
+            hfp.AgIndicatorState.service(),
+            hfp.AgIndicatorState.signal(),
+            hfp.AgIndicatorState.roam(),
+            hfp.AgIndicatorState.battchg(),
+        ],
+        supported_hf_indicators=[
+            hfp.HfIndicator.ENHANCED_SAFETY,
+            hfp.HfIndicator.BATTERY_LEVEL,
+        ],
+        supported_ag_call_hold_operations=[],
+        supported_audio_codecs=[hfp.AudioCodec.CVSD, hfp.AudioCodec.MSBC],
     )
-    print(color('==================================', 'blue'))
-    print(color('Handsfree Services:', 'yellow'))
-    rfcomm_channels = []
-    # pylint: disable-next=too-many-nested-blocks
-    for attribute_list in search_result:
-        # Look for the RFCOMM Channel number
-        protocol_descriptor_list = ServiceAttribute.find_attribute_in_list(
-            attribute_list, SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID
+
+
+def send_message(type: str, **kwargs) -> None:
+    if ws:
+        asyncio.create_task(ws.send(json.dumps({'type': type, **kwargs})))
+
+
+def on_speaker_volume(level: int):
+    send_message(type='speaker_volume', level=level)
+
+
+def on_microphone_volume(level: int):
+    send_message(type='microphone_volume', level=level)
+
+
+def on_sco_state_change(codec: int):
+    if codec == hfp.AudioCodec.CVSD:
+        sample_rate = 8000
+    elif codec == hfp.AudioCodec.MSBC:
+        sample_rate = 16000
+    else:
+        sample_rate = 0
+
+    send_message(type='sco_state_change', sample_rate=sample_rate)
+
+
+def on_sco_packet(packet: hci.HCI_SynchronousDataPacket):
+    if ws:
+        asyncio.create_task(ws.send(packet.data))
+    if source_file and (pcm_data := source_file.read(packet.data_total_length)):
+        assert ag_protocol
+        host = ag_protocol.dlc.multiplexer.l2cap_channel.connection.device.host
+        host.send_hci_packet(
+            hci.HCI_SynchronousDataPacket(
+                connection_handle=packet.connection_handle,
+                packet_status=0,
+                data_total_length=len(pcm_data),
+                data=pcm_data,
+            )
         )
-        if protocol_descriptor_list:
-            for protocol_descriptor in protocol_descriptor_list.value:
-                if len(protocol_descriptor.value) >= 2:
-                    if protocol_descriptor.value[0].value == BT_RFCOMM_PROTOCOL_ID:
-                        print(color('SERVICE:', 'green'))
-                        print(
-                            color('  RFCOMM Channel:', 'cyan'),
-                            protocol_descriptor.value[1].value,
-                        )
-                        rfcomm_channels.append(protocol_descriptor.value[1].value)
-
-                        # List profiles
-                        bluetooth_profile_descriptor_list = (
-                            ServiceAttribute.find_attribute_in_list(
-                                attribute_list,
-                                SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID,
-                            )
-                        )
-                        if bluetooth_profile_descriptor_list:
-                            if bluetooth_profile_descriptor_list.value:
-                                if (
-                                    bluetooth_profile_descriptor_list.value[0].type
-                                    == DataElement.SEQUENCE
-                                ):
-                                    bluetooth_profile_descriptors = (
-                                        bluetooth_profile_descriptor_list.value
-                                    )
-                                else:
-                                    # Sometimes, instead of a list of lists, we just
-                                    # find a list. Fix that
-                                    bluetooth_profile_descriptors = [
-                                        bluetooth_profile_descriptor_list
-                                    ]
-
-                                print(color('  Profiles:', 'green'))
-                                for (
-                                    bluetooth_profile_descriptor
-                                ) in bluetooth_profile_descriptors:
-                                    version_major = (
-                                        bluetooth_profile_descriptor.value[1].value >> 8
-                                    )
-                                    version_minor = (
-                                        bluetooth_profile_descriptor.value[1].value
-                                        & 0xFF
-                                    )
-                                    print(
-                                        '    '
-                                        f'{bluetooth_profile_descriptor.value[0].value}'
-                                        f' - version {version_major}.{version_minor}'
-                                    )
-
-                        # List service classes
-                        service_class_id_list = ServiceAttribute.find_attribute_in_list(
-                            attribute_list, SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID
-                        )
-                        if service_class_id_list:
-                            if service_class_id_list.value:
-                                print(color('  Service Classes:', 'green'))
-                                for service_class_id in service_class_id_list.value:
-                                    print('   ', service_class_id.value)
-
-    await sdp_client.disconnect()
-    return rfcomm_channels
+
+
+def on_hfp_state_change(connected: bool):
+    send_message(type='hfp_state_change', connected=connected)
+
+
+async def ws_server(ws_client: websockets.WebSocketServerProtocol, path: str):
+    del path
+    global ws
+    ws = ws_client
+
+    async for message in ws_client:
+        if not ag_protocol:
+            continue
+
+        json_message = json.loads(message)
+        message_type = json_message['type']
+        connection = ag_protocol.dlc.multiplexer.l2cap_channel.connection
+        device = connection.device
+
+        try:
+            if message_type == 'at_response':
+                ag_protocol.send_response(json_message['response'])
+            elif message_type == 'ag_indicator':
+                ag_protocol.update_ag_indicator(
+                    hfp.AgIndicator(json_message['indicator']),
+                    int(json_message['value']),
+                )
+            elif message_type == 'negotiate_codec':
+                codec = hfp.AudioCodec(int(json_message['codec']))
+                await ag_protocol.negotiate_codec(codec)
+            elif message_type == 'connect_sco':
+                if ag_protocol.active_codec == hfp.AudioCodec.CVSD:
+                    esco_param = hfp.ESCO_PARAMETERS[
+                        hfp.DefaultCodecParameters.ESCO_CVSD_S4
+                    ]
+                elif ag_protocol.active_codec == hfp.AudioCodec.MSBC:
+                    esco_param = hfp.ESCO_PARAMETERS[
+                        hfp.DefaultCodecParameters.ESCO_MSBC_T2
+                    ]
+                else:
+                    raise ValueError(f'Unsupported codec {codec}')
+
+                await device.send_command(
+                    hci.HCI_Enhanced_Setup_Synchronous_Connection_Command(
+                        connection_handle=connection.handle, **esco_param.asdict()
+                    )
+                )
+            elif message_type == 'disconnect_sco':
+                # Copy the values to avoid iteration error.
+                for sco_link in list(device.sco_links.values()):
+                    await sco_link.disconnect()
+            elif message_type == 'update_calls':
+                ag_protocol.calls = [
+                    hfp.CallInfo(
+                        index=int(call['index']),
+                        direction=hfp.CallInfoDirection(int(call['direction'])),
+                        status=hfp.CallInfoStatus(int(call['status'])),
+                        number=call['number'],
+                        multi_party=hfp.CallInfoMultiParty.NOT_IN_CONFERENCE,
+                        mode=hfp.CallInfoMode.VOICE,
+                    )
+                    for call in json_message['calls']
+                ]
+
+        except Exception as e:
+            send_message(type='error', message=e)
 
 
 # -----------------------------------------------------------------------------
-async def main():
-    if len(sys.argv) < 4:
+async def main() -> None:
+    if len(sys.argv) < 3:
         print(
             'Usage: run_hfp_gateway.py <device-config> <transport-spec> '
-            '<bluetooth-address>'
+            '[bluetooth-address] [wav-file-for-source]'
         )
         print(
-            '  specifying a channel number, or "discover" to list all RFCOMM channels'
+            'example: run_hfp_gateway.py hfp_gateway.json usb:0 E1:CA:72:48:C4:E8 sample.wav'
         )
-        print('example: run_hfp_gateway.py hfp_gateway.json usb:0 E1:CA:72:48:C4:E8')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
         await device.power_on()
 
-        # Connect to a peer
-        target_address = sys.argv[3]
-        print(f'=== Connecting to {target_address}...')
-        connection = await device.connect(target_address, transport=BT_BR_EDR_TRANSPORT)
-        print(f'=== Connected to {connection.peer_address}!')
-
-        # Get a list of all the Handsfree services (should only be 1)
-        channels = await list_rfcomm_channels(device, connection)
-        if len(channels) == 0:
-            print('!!! no service found')
-            return
-
-        # Pick the first one
-        channel = channels[0]
-
-        # Request authentication
-        print('*** Authenticating...')
-        await connection.authenticate()
-        print('*** Authenticated')
-
-        # Enable encryption
-        print('*** Enabling encryption...')
-        await connection.encrypt()
-        print('*** Encryption on')
-
-        # Create a client and start it
-        print('@@@ Starting to RFCOMM client...')
-        rfcomm_client = rfcomm.Client(connection)
-        rfcomm_mux = await rfcomm_client.start()
-        print('@@@ Started')
-
-        print(f'### Opening session for channel {channel}...')
-        try:
-            session = await rfcomm_mux.open_dlc(channel)
-            print('### Session open', session)
-        except bumble.core.ConnectionError as error:
-            print(f'### Session open failed: {error}')
-            await rfcomm_mux.disconnect()
-            print('@@@ Disconnected from RFCOMM server')
-            return
-
-        def on_sco(connection_handle: int, packet: HCI_SynchronousDataPacket):
-            # Reset packet and loopback
-            packet.packet_status = 0
-            device.host.send_hci_packet(packet)
-
-        device.host.on('sco_packet', on_sco)
-
-        # Protocol loop (just for testing at this point)
-        protocol = hfp.HfpProtocol(session)
-        while True:
-            line = await protocol.next_line()
-
-            if line.startswith('AT+BRSF='):
-                protocol.send_response_line('+BRSF: 30')
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+CIND=?'):
-                protocol.send_response_line(
-                    '+CIND: ("call",(0,1)),("callsetup",(0-3)),("service",(0-1)),'
-                    '("signal",(0-5)),("roam",(0,1)),("battchg",(0-5)),'
-                    '("callheld",(0-2))'
-                )
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+CIND?'):
-                protocol.send_response_line('+CIND: 0,0,1,4,1,5,0')
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+CMER='):
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+CHLD=?'):
-                protocol.send_response_line('+CHLD: 0')
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+BTRH?'):
-                protocol.send_response_line('+BTRH: 0')
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+CLIP='):
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+VGS='):
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+BIA='):
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+BVRA='):
-                protocol.send_response_line(
-                    '+BVRA: 1,1,12AA,1,1,"Message 1 from Janina"'
-                )
-            elif line.startswith('AT+XEVENT='):
-                protocol.send_response_line('OK')
-            elif line.startswith('AT+XAPL='):
-                protocol.send_response_line('OK')
-            else:
-                print(color('UNSUPPORTED AT COMMAND', 'red'))
-                protocol.send_response_line('ERROR')
-
-        await hci_source.wait_for_termination()
+        rfcomm_server = rfcomm.Server(device)
+        configuration = _default_configuration()
+
+        def on_dlc(dlc: rfcomm.DLC):
+            global ag_protocol
+            ag_protocol = hfp.AgProtocol(dlc, configuration)
+            ag_protocol.on('speaker_volume', on_speaker_volume)
+            ag_protocol.on('microphone_volume', on_microphone_volume)
+            on_hfp_state_change(True)
+            dlc.multiplexer.l2cap_channel.on(
+                'close', lambda: on_hfp_state_change(False)
+            )
+
+        channel = rfcomm_server.listen(on_dlc)
+        device.sdp_service_records = {
+            1: hfp.make_ag_sdp_records(1, channel, configuration)
+        }
+
+        def on_sco_connection(sco_link: ScoLink):
+            assert ag_protocol
+            on_sco_state_change(ag_protocol.active_codec)
+            sco_link.on('disconnection', lambda _: on_sco_state_change(0))
+            sco_link.sink = on_sco_packet
+
+        device.on('sco_connection', on_sco_connection)
+        if len(sys.argv) >= 4:
+            # Connect to a peer
+            target_address = sys.argv[3]
+            print(f'=== Connecting to {target_address}...')
+            connection = await device.connect(
+                target_address, transport=BT_BR_EDR_TRANSPORT
+            )
+            print(f'=== Connected to {connection.peer_address}!')
+
+            # Get a list of all the Handsfree services (should only be 1)
+            if not (hfp_record := await hfp.find_hf_sdp_record(connection)):
+                print('!!! no service found')
+                return
+
+            # Pick the first one
+            channel, version, hf_sdp_features = hfp_record
+            print(f'HF version: {version}')
+            print(f'HF features: {hf_sdp_features}')
+
+            # Request authentication
+            print('*** Authenticating...')
+            await connection.authenticate()
+            print('*** Authenticated')
+
+            # Enable encryption
+            print('*** Enabling encryption...')
+            await connection.encrypt()
+            print('*** Encryption on')
+
+            # Create a client and start it
+            print('@@@ Starting to RFCOMM client...')
+            rfcomm_client = rfcomm.Client(connection)
+            rfcomm_mux = await rfcomm_client.start()
+            print('@@@ Started')
+
+            print(f'### Opening session for channel {channel}...')
+            try:
+                session = await rfcomm_mux.open_dlc(channel)
+                print('### Session open', session)
+            except bumble.core.ConnectionError as error:
+                print(f'### Session open failed: {error}')
+                await rfcomm_mux.disconnect()
+                print('@@@ Disconnected from RFCOMM server')
+                return
+
+            on_dlc(session)
+
+        await websockets.serve(ws_server, port=8888)
+
+        if len(sys.argv) >= 5:
+            global source_file
+            source_file = open(sys.argv[4], 'rb')
+            # Skip header
+            source_file.seek(44)
+
+        await hci_transport.source.terminated
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_hfp_handsfree.py b/examples/run_hfp_handsfree.py
index f4e445e..5433284 100644
--- a/examples/run_hfp_handsfree.py
+++ b/examples/run_hfp_handsfree.py
@@ -16,6 +16,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import contextlib
 import sys
 import os
 import logging
@@ -31,39 +32,16 @@ from bumble.transport import open_transport_or_link
 from bumble import hfp
 from bumble.hfp import HfProtocol
 
-
-# -----------------------------------------------------------------------------
-class UiServer:
-    protocol: Optional[HfProtocol] = None
-
-    async def start(self):
-        """Start a Websocket server to receive events from a web page."""
-
-        async def serve(websocket, _path):
-            while True:
-                try:
-                    message = await websocket.recv()
-                    print('Received: ', str(message))
-
-                    parsed = json.loads(message)
-                    message_type = parsed['type']
-                    if message_type == 'at_command':
-                        if self.protocol is not None:
-                            await self.protocol.execute_command(parsed['command'])
-
-                except websockets.exceptions.ConnectionClosedOK:
-                    pass
-
-        # pylint: disable=no-member
-        await websockets.serve(serve, 'localhost', 8989)
+ws: Optional[websockets.WebSocketServerProtocol] = None
+hf_protocol: Optional[HfProtocol] = None
 
 
 # -----------------------------------------------------------------------------
-def on_dlc(dlc: rfcomm.DLC, configuration: hfp.Configuration):
+def on_dlc(dlc: rfcomm.DLC, configuration: hfp.HfConfiguration):
     print('*** DLC connected', dlc)
-    protocol = HfProtocol(dlc, configuration)
-    UiServer.protocol = protocol
-    asyncio.create_task(protocol.run())
+    global hf_protocol
+    hf_protocol = HfProtocol(dlc, configuration)
+    asyncio.create_task(hf_protocol.run())
 
     def on_sco_request(connection: Connection, link_type: int, protocol: HfProtocol):
         if connection == protocol.dlc.multiplexer.l2cap_channel.connection:
@@ -88,7 +66,7 @@ def on_dlc(dlc: rfcomm.DLC, configuration: hfp.Configuration):
                 ),
             )
 
-    handler = functools.partial(on_sco_request, protocol=protocol)
+    handler = functools.partial(on_sco_request, protocol=hf_protocol)
     dlc.multiplexer.l2cap_channel.connection.device.on('sco_request', handler)
     dlc.multiplexer.l2cap_channel.once(
         'close',
@@ -97,21 +75,28 @@ def on_dlc(dlc: rfcomm.DLC, configuration: hfp.Configuration):
         ),
     )
 
+    def on_ag_indicator(indicator):
+        global ws
+        if ws:
+            asyncio.create_task(ws.send(str(indicator)))
+
+    hf_protocol.on('ag_indicator', on_ag_indicator)
+
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print('Usage: run_classic_hfp.py <device-config> <transport-spec>')
         print('example: run_classic_hfp.py classic2.json usb:04b4:f901')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Hands-Free profile configuration.
         # TODO: load configuration from file.
-        configuration = hfp.Configuration(
+        configuration = hfp.HfConfiguration(
             supported_hf_features=[
                 hfp.HfFeature.THREE_WAY_CALLING,
                 hfp.HfFeature.REMOTE_VOLUME_CONTROL,
@@ -131,7 +116,9 @@ async def main():
         )
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Create and register a server
@@ -143,7 +130,9 @@ async def main():
 
         # Advertise the HFP RFComm channel in the SDP
         device.sdp_service_records = {
-            0x00010001: hfp.sdp_records(0x00010001, channel_number, configuration)
+            0x00010001: hfp.make_hf_sdp_records(
+                0x00010001, channel_number, configuration
+            )
         }
 
         # Let's go!
@@ -154,10 +143,32 @@ async def main():
         await device.set_connectable(True)
 
         # Start the UI websocket server to offer a few buttons and input boxes
-        ui_server = UiServer()
-        await ui_server.start()
+        async def serve(websocket: websockets.WebSocketServerProtocol, _path):
+            global ws
+            ws = websocket
+            async for message in websocket:
+                with contextlib.suppress(websockets.exceptions.ConnectionClosedOK):
+                    print('Received: ', str(message))
+
+                    parsed = json.loads(message)
+                    message_type = parsed['type']
+                    if message_type == 'at_command':
+                        if hf_protocol is not None:
+                            response = str(
+                                await hf_protocol.execute_command(
+                                    parsed['command'],
+                                    response_type=hfp.AtResponseType.MULTIPLE,
+                                )
+                            )
+                            await websocket.send(response)
+                    elif message_type == 'query_call':
+                        if hf_protocol:
+                            response = str(await hf_protocol.query_current_calls())
+                            await websocket.send(response)
+
+        await websockets.serve(serve, 'localhost', 8989)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_hid_device.py b/examples/run_hid_device.py
index 9aebfc2..2287be0 100644
--- a/examples/run_hid_device.py
+++ b/examples/run_hid_device.py
@@ -229,6 +229,7 @@ HID_REPORT_MAP = bytes(  # Text String, 50 Octet Report Descriptor
 # Default protocol mode set to report protocol
 protocol_mode = Message.ProtocolMode.REPORT_PROTOCOL
 
+
 # -----------------------------------------------------------------------------
 def sdp_records():
     service_record_handle = 0x00010002
@@ -427,6 +428,7 @@ class DeviceData:
 # Device's live data - Mouse and Keyboard will be stored in this
 deviceData = DeviceData()
 
+
 # -----------------------------------------------------------------------------
 async def keyboard_device(hid_device):
 
@@ -487,7 +489,7 @@ async def keyboard_device(hid_device):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print(
             'Usage: python run_hid_device.py <device-config> <transport-spec> <command>'
@@ -599,11 +601,13 @@ async def main():
         asyncio.create_task(handle_virtual_cable_unplug())
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Create and register HID device
@@ -740,7 +744,7 @@ async def main():
             print("Executing in Web mode")
             await keyboard_device(hid_device)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_hid_host.py b/examples/run_hid_host.py
index 7519b4e..cc17cc1 100644
--- a/examples/run_hid_host.py
+++ b/examples/run_hid_host.py
@@ -275,7 +275,7 @@ async def get_stream_reader(pipe) -> asyncio.StreamReader:
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print(
             'Usage: run_hid_host.py <device-config> <transport-spec> '
@@ -324,11 +324,13 @@ async def main():
         asyncio.create_task(handle_virtual_cable_unplug())
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< CONNECTED')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Create HID host and start it
@@ -557,7 +559,7 @@ async def main():
             # Interrupt Channel
             await hid_host.connect_interrupt_channel()
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_notifier.py b/examples/run_notifier.py
index 5f6def3..869e716 100644
--- a/examples/run_notifier.py
+++ b/examples/run_notifier.py
@@ -57,18 +57,20 @@ def on_my_characteristic_subscription(peer, enabled):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 3:
         print('Usage: run_notifier.py <device-config> <transport-spec>')
         print('example: run_notifier.py device1.json usb:0')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device to manage the host
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.listener = Listener(device)
 
         # Add a few entries to the device's GATT server
diff --git a/examples/run_rfcomm_client.py b/examples/run_rfcomm_client.py
index 39ee776..9232dc9 100644
--- a/examples/run_rfcomm_client.py
+++ b/examples/run_rfcomm_client.py
@@ -165,7 +165,7 @@ async def tcp_server(tcp_port, rfcomm_session):
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 5:
         print(
             'Usage: run_rfcomm_client.py <device-config> <transport-spec> '
@@ -178,11 +178,13 @@ async def main():
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
         await device.power_on()
 
@@ -192,8 +194,8 @@ async def main():
         connection = await device.connect(target_address, transport=BT_BR_EDR_TRANSPORT)
         print(f'=== Connected to {connection.peer_address}!')
 
-        channel = sys.argv[4]
-        if channel == 'discover':
+        channel_str = sys.argv[4]
+        if channel_str == 'discover':
             await list_rfcomm_channels(connection)
             return
 
@@ -213,7 +215,7 @@ async def main():
         rfcomm_mux = await rfcomm_client.start()
         print('@@@ Started')
 
-        channel = int(channel)
+        channel = int(channel_str)
         print(f'### Opening session for channel {channel}...')
         try:
             session = await rfcomm_mux.open_dlc(channel)
@@ -229,7 +231,7 @@ async def main():
             tcp_port = int(sys.argv[5])
             asyncio.create_task(tcp_server(tcp_port, session))
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_rfcomm_server.py b/examples/run_rfcomm_server.py
index 41915a4..14bc7eb 100644
--- a/examples/run_rfcomm_server.py
+++ b/examples/run_rfcomm_server.py
@@ -107,7 +107,7 @@ class TcpServer:
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 4:
         print(
             'Usage: run_rfcomm_server.py <device-config> <transport-spec> '
@@ -124,11 +124,13 @@ async def main():
         uuid = 'E6D55659-C8B4-4B85-96BB-B1143AF6D3AE'
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[2]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
         print('<<< connected')
 
         # Create a device
-        device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
         device.classic_enabled = True
 
         # Create a TCP server
@@ -153,7 +155,7 @@ async def main():
         await device.set_discoverable(True)
         await device.set_connectable(True)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_scanner.py b/examples/run_scanner.py
index 4a094b9..5748b48 100644
--- a/examples/run_scanner.py
+++ b/examples/run_scanner.py
@@ -20,27 +20,31 @@ import sys
 import os
 import logging
 from bumble.colors import color
-
+from bumble.hci import Address
 from bumble.device import Device
 from bumble.transport import open_transport_or_link
 
 
 # -----------------------------------------------------------------------------
-async def main():
+async def main() -> None:
     if len(sys.argv) < 2:
         print('Usage: run_scanner.py <transport-spec> [filter]')
         print('example: run_scanner.py usb:0')
         return
 
     print('<<< connecting to HCI...')
-    async with await open_transport_or_link(sys.argv[1]) as (hci_source, hci_sink):
+    async with await open_transport_or_link(sys.argv[1]) as hci_transport:
         print('<<< connected')
         filter_duplicates = len(sys.argv) == 3 and sys.argv[2] == 'filter'
 
-        device = Device.with_hci('Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink)
+        device = Device.with_hci(
+            'Bumble',
+            Address('F0:F1:F2:F3:F4:F5'),
+            hci_transport.source,
+            hci_transport.sink,
+        )
 
-        @device.on('advertisement')
-        def _(advertisement):
+        def on_adv(advertisement):
             address_type_string = ('PUBLIC', 'RANDOM', 'PUBLIC_ID', 'RANDOM_ID')[
                 advertisement.address.address_type
             ]
@@ -67,10 +71,11 @@ async def main():
                 f'{advertisement.data.to_string(separator)}'
             )
 
+        device.on('advertisement', on_adv)
         await device.power_on()
         await device.start_scanning(filter_duplicates=filter_duplicates)
 
-        await hci_source.wait_for_termination()
+        await hci_transport.source.wait_for_termination()
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_unicast_server.py b/examples/run_unicast_server.py
index 4fac1d6..95ae551 100644
--- a/examples/run_unicast_server.py
+++ b/examples/run_unicast_server.py
@@ -16,20 +16,28 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import datetime
+import functools
 import logging
 import sys
 import os
+import io
 import struct
 import secrets
+
+from typing import Dict
+
 from bumble.core import AdvertisingData
-from bumble.device import Device, CisLink, AdvertisingParameters
+from bumble.device import Device
 from bumble.hci import (
     CodecID,
     CodingFormat,
-    OwnAddressType,
     HCI_IsoDataPacket,
 )
 from bumble.profiles.bap import (
+    AseStateMachine,
+    UnicastServerAdvertisingData,
+    CodecSpecificConfiguration,
     CodecSpecificCapabilities,
     ContextType,
     AudioLocation,
@@ -45,6 +53,32 @@ from bumble.profiles.csip import CoordinatedSetIdentificationService, SirkType
 from bumble.transport import open_transport_or_link
 
 
+def _sink_pac_record() -> PacRecord:
+    return PacRecord(
+        coding_format=CodingFormat(CodecID.LC3),
+        codec_specific_capabilities=CodecSpecificCapabilities(
+            supported_sampling_frequencies=(
+                SupportedSamplingFrequency.FREQ_8000
+                | SupportedSamplingFrequency.FREQ_16000
+                | SupportedSamplingFrequency.FREQ_24000
+                | SupportedSamplingFrequency.FREQ_32000
+                | SupportedSamplingFrequency.FREQ_48000
+            ),
+            supported_frame_durations=(
+                SupportedFrameDuration.DURATION_7500_US_SUPPORTED
+                | SupportedFrameDuration.DURATION_10000_US_SUPPORTED
+            ),
+            supported_audio_channel_count=[1, 2],
+            min_octets_per_codec_frame=26,
+            max_octets_per_codec_frame=240,
+            supported_max_codec_frames_per_sdu=2,
+        ),
+    )
+
+
+file_outputs: Dict[AseStateMachine, io.BufferedWriter] = {}
+
+
 # -----------------------------------------------------------------------------
 async def main() -> None:
     if len(sys.argv) < 3:
@@ -71,49 +105,17 @@ async def main() -> None:
             PublishedAudioCapabilitiesService(
                 supported_source_context=ContextType.PROHIBITED,
                 available_source_context=ContextType.PROHIBITED,
-                supported_sink_context=ContextType.MEDIA,
-                available_sink_context=ContextType.MEDIA,
+                supported_sink_context=ContextType(0xFF),  # All context types
+                available_sink_context=ContextType(0xFF),  # All context types
                 sink_audio_locations=(
                     AudioLocation.FRONT_LEFT | AudioLocation.FRONT_RIGHT
                 ),
-                sink_pac=[
-                    # Codec Capability Setting 16_2
-                    PacRecord(
-                        coding_format=CodingFormat(CodecID.LC3),
-                        codec_specific_capabilities=CodecSpecificCapabilities(
-                            supported_sampling_frequencies=(
-                                SupportedSamplingFrequency.FREQ_16000
-                            ),
-                            supported_frame_durations=(
-                                SupportedFrameDuration.DURATION_10000_US_SUPPORTED
-                            ),
-                            supported_audio_channel_counts=[1],
-                            min_octets_per_codec_frame=40,
-                            max_octets_per_codec_frame=40,
-                            supported_max_codec_frames_per_sdu=1,
-                        ),
-                    ),
-                    # Codec Capability Setting 24_2
-                    PacRecord(
-                        coding_format=CodingFormat(CodecID.LC3),
-                        codec_specific_capabilities=CodecSpecificCapabilities(
-                            supported_sampling_frequencies=(
-                                SupportedSamplingFrequency.FREQ_48000
-                            ),
-                            supported_frame_durations=(
-                                SupportedFrameDuration.DURATION_10000_US_SUPPORTED
-                            ),
-                            supported_audio_channel_counts=[1],
-                            min_octets_per_codec_frame=120,
-                            max_octets_per_codec_frame=120,
-                            supported_max_codec_frames_per_sdu=1,
-                        ),
-                    ),
-                ],
+                sink_pac=[_sink_pac_record()],
             )
         )
 
-        device.add_service(AudioStreamControlService(device, sink_ase_id=[1, 2]))
+        ascs = AudioStreamControlService(device, sink_ase_id=[1], source_ase_id=[2])
+        device.add_service(ascs)
 
         advertising_data = (
             bytes(
@@ -141,45 +143,59 @@ async def main() -> None:
                 )
             )
             + csis.get_advertising_data()
-        )
-        subprocess = await asyncio.create_subprocess_shell(
-            f'dlc3 | ffplay pipe:0',
-            stdin=asyncio.subprocess.PIPE,
-            stdout=asyncio.subprocess.PIPE,
-            stderr=asyncio.subprocess.PIPE,
-        )
-
-        stdin = subprocess.stdin
-        assert stdin
-
-        # Write a fake LC3 header to dlc3.
-        stdin.write(
-            bytes([0x1C, 0xCC])  # Header.
-            + struct.pack(
-                '<HHHHHHI',
-                18,  # Header length.
-                48000 // 100,  # Sampling Rate(/100Hz).
-                0,  # Bitrate(unused).
-                1,  # Channels.
-                10000 // 10,  # Frame duration(/10us).
-                0,  # RFU.
-                0x0FFFFFFF,  # Frame counts.
-            )
+            + bytes(UnicastServerAdvertisingData())
         )
 
-        def on_pdu(pdu: HCI_IsoDataPacket):
+        def on_pdu(ase: AseStateMachine, pdu: HCI_IsoDataPacket):
             # LC3 format: |frame_length(2)| + |frame(length)|.
+            sdu = b''
             if pdu.iso_sdu_length:
-                stdin.write(struct.pack('<H', pdu.iso_sdu_length))
-            stdin.write(pdu.iso_sdu_fragment)
-
-        def on_cis(cis_link: CisLink):
-            cis_link.on('pdu', on_pdu)
-
-        device.once('cis_establishment', on_cis)
+                sdu = struct.pack('<H', pdu.iso_sdu_length)
+            sdu += pdu.iso_sdu_fragment
+            file_outputs[ase].write(sdu)
+
+        def on_ase_state_change(
+            state: AseStateMachine.State,
+            ase: AseStateMachine,
+        ) -> None:
+            if state != AseStateMachine.State.STREAMING:
+                if file_output := file_outputs.pop(ase):
+                    file_output.close()
+            else:
+                file_output = open(f'{datetime.datetime.now().isoformat()}.lc3', 'wb')
+                codec_configuration = ase.codec_specific_configuration
+                assert isinstance(codec_configuration, CodecSpecificConfiguration)
+                # Write a LC3 header.
+                file_output.write(
+                    bytes([0x1C, 0xCC])  # Header.
+                    + struct.pack(
+                        '<HHHHHHI',
+                        18,  # Header length.
+                        codec_configuration.sampling_frequency.hz
+                        // 100,  # Sampling Rate(/100Hz).
+                        0,  # Bitrate(unused).
+                        bin(codec_configuration.audio_channel_allocation).count(
+                            '1'
+                        ),  # Channels.
+                        codec_configuration.frame_duration.us
+                        // 10,  # Frame duration(/10us).
+                        0,  # RFU.
+                        0x0FFFFFFF,  # Frame counts.
+                    )
+                )
+                file_outputs[ase] = file_output
+                assert ase.cis_link
+                ase.cis_link.sink = functools.partial(on_pdu, ase)
+
+        for ase in ascs.ase_state_machines.values():
+            ase.on(
+                'state_change',
+                functools.partial(on_ase_state_change, ase=ase),
+            )
 
-        advertising_set = await device.create_advertising_set(
+        await device.create_advertising_set(
             advertising_data=advertising_data,
+            auto_restart=True,
         )
 
         await hci_transport.source.terminated
diff --git a/examples/run_vcp_renderer.py b/examples/run_vcp_renderer.py
index b695956..0cffbae 100644
--- a/examples/run_vcp_renderer.py
+++ b/examples/run_vcp_renderer.py
@@ -31,6 +31,7 @@ from bumble.hci import (
     OwnAddressType,
 )
 from bumble.profiles.bap import (
+    UnicastServerAdvertisingData,
     CodecSpecificCapabilities,
     ContextType,
     AudioLocation,
@@ -101,7 +102,7 @@ async def main() -> None:
                             supported_frame_durations=(
                                 SupportedFrameDuration.DURATION_10000_US_SUPPORTED
                             ),
-                            supported_audio_channel_counts=[1],
+                            supported_audio_channel_count=[1],
                             min_octets_per_codec_frame=120,
                             max_octets_per_codec_frame=120,
                             supported_max_codec_frames_per_sdu=1,
@@ -151,6 +152,7 @@ async def main() -> None:
                 )
             )
             + csis.get_advertising_data()
+            + bytes(UnicastServerAdvertisingData())
         )
 
         await device.create_advertising_set(
diff --git a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/SocketClient.kt b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/SocketClient.kt
index bd5b7f4..46a014a 100644
--- a/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/SocketClient.kt
+++ b/extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/SocketClient.kt
@@ -56,13 +56,19 @@ class SocketClient(private val viewModel: AppViewModel, private val socket: Blue
 
             thread {
                 socketDataSource.receive()
+                socket.close()
+                sender.abort()
             }
 
             Log.info("Startup delay: $DEFAULT_STARTUP_DELAY")
             Thread.sleep(DEFAULT_STARTUP_DELAY.toLong());
             Log.info("Starting to send")
 
-            sender.run()
+            try {
+                sender.run()
+            } catch (error: IOException) {
+                Log.info("run ended abruptly")
+            }
             cleanup()
         }
     }
diff --git a/rust/CHANGELOG.md b/rust/CHANGELOG.md
index 2cfed4e..ce575a2 100644
--- a/rust/CHANGELOG.md
+++ b/rust/CHANGELOG.md
@@ -1,7 +1,10 @@
-# Next
+# 0.2.0
 
 - Code-gen company ID table
+- Unstable support for extended advertisements
+- CLI tools for downloading Realtek firmware
+- PDL-generated types for HCI commands
 
 # 0.1.0
 
-- Initial release
\ No newline at end of file
+- Initial release
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 3339339..5305f9f 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -182,7 +182,7 @@ dependencies = [
 
 [[package]]
 name = "bumble"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "anyhow",
  "bytes",
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 8106114..73c9ac3 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "bumble"
 description = "Rust API for the Bumble Bluetooth stack"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 license = "Apache-2.0"
 homepage = "https://google.github.io/bumble/index.html"
diff --git a/rust/README.md b/rust/README.md
index 15a19b9..e08ef25 100644
--- a/rust/README.md
+++ b/rust/README.md
@@ -37,6 +37,11 @@ PYTHONPATH=..:[virtualenv site-packages] \
     cargo run --features bumble-tools --bin bumble -- --help
 ```
 
+Notable subcommands:
+
+- `firmware realtek download`: download Realtek firmware for various chipsets so that it can be automatically loaded when needed
+- `usb probe`: show USB devices, highlighting the ones usable for Bluetooth
+
 # Development
 
 Run the tests:
@@ -63,4 +68,4 @@ To regenerate the assigned number tables based on the Python codebase:
 
 ```
 PYTHONPATH=.. cargo run --bin gen-assigned-numbers --features dev-tools
-```
\ No newline at end of file
+```
diff --git a/rust/src/wrapper/controller.rs b/rust/src/wrapper/controller.rs
index 4f19dd6..cec10db 100644
--- a/rust/src/wrapper/controller.rs
+++ b/rust/src/wrapper/controller.rs
@@ -35,7 +35,7 @@ impl Controller {
     /// module specifies the defaults. Must be called from a thread with a Python event loop, which
     /// should be true on `tokio::main` and `async_std::main`.
     ///
-    /// For more info, see https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars.
+    /// For more info, see <https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars>.
     pub async fn new(
         name: &str,
         host_source: Option<TransportSource>,
diff --git a/rust/src/wrapper/hci.rs b/rust/src/wrapper/hci.rs
index 533fe21..52480c8 100644
--- a/rust/src/wrapper/hci.rs
+++ b/rust/src/wrapper/hci.rs
@@ -149,7 +149,7 @@ impl ToPyObject for Address {
 
 /// An error meaning that the u64 value did not represent a valid BT address.
 #[derive(Debug)]
-pub struct InvalidAddress(u64);
+pub struct InvalidAddress(#[allow(unused)] u64);
 
 impl TryInto<packets::Address> for Address {
     type Error = ConversionError<InvalidAddress>;
diff --git a/rust/src/wrapper/l2cap.rs b/rust/src/wrapper/l2cap.rs
index 5e0752e..06fbc52 100644
--- a/rust/src/wrapper/l2cap.rs
+++ b/rust/src/wrapper/l2cap.rs
@@ -71,7 +71,7 @@ impl LeConnectionOrientedChannel {
     /// Must be called from a thread with a Python event loop, which should be true on
     /// `tokio::main` and `async_std::main`.
     ///
-    /// For more info, see https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars.
+    /// For more info, see <https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars>.
     pub async fn disconnect(&mut self) -> PyResult<()> {
         Python::with_gil(|py| {
             self.0
diff --git a/setup.cfg b/setup.cfg
index e29288b..44d8541 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -33,18 +33,17 @@ include_package_data = True
 install_requires =
     aiohttp ~= 3.8; platform_system!='Emscripten'
     appdirs >= 1.4; platform_system!='Emscripten'
-    bt-test-interfaces >= 0.0.2; platform_system!='Emscripten'
-    click == 8.1.3; platform_system!='Emscripten'
+    click >= 8.1.3; platform_system!='Emscripten'
     cryptography == 39; platform_system!='Emscripten'
     # Pyodide bundles a version of cryptography that is built for wasm, which may not match the
     # versions available on PyPI. Relax the version requirement since it's better than being
     # completely unable to import the package in case of version mismatch.
     cryptography >= 39.0; platform_system=='Emscripten'
-    grpcio == 1.57.0; platform_system!='Emscripten'
+    grpcio >= 1.62.1; platform_system!='Emscripten'
     humanize >= 4.6.0; platform_system!='Emscripten'
     libusb1 >= 2.0.1; platform_system!='Emscripten'
     libusb-package == 1.0.26.1; platform_system!='Emscripten'
-    platformdirs == 3.10.0; platform_system!='Emscripten'
+    platformdirs >= 3.10.0; platform_system!='Emscripten'
     prompt_toolkit >= 3.0.16; platform_system!='Emscripten'
     prettytable >= 3.6.0; platform_system!='Emscripten'
     protobuf >= 3.12.4; platform_system!='Emscripten'
@@ -63,6 +62,7 @@ console_scripts =
     bumble-gatt-dump = bumble.apps.gatt_dump:main
     bumble-hci-bridge = bumble.apps.hci_bridge:main
     bumble-l2cap-bridge = bumble.apps.l2cap_bridge:main
+    bumble-rfcomm-bridge = bumble.apps.rfcomm_bridge:main
     bumble-pair = bumble.apps.pair:main
     bumble-scan = bumble.apps.scan:main
     bumble-show = bumble.apps.show:main
@@ -82,24 +82,27 @@ console_scripts =
 build =
     build >= 0.7
 test =
-    pytest >= 8.0
-    pytest-asyncio == 0.21.1
+    pytest >= 8.2
+    pytest-asyncio >= 0.23.5
     pytest-html >= 3.2.0
     coverage >= 6.4
 development =
-    black == 22.10
-    grpcio-tools >= 1.57.0
+    black == 24.3
+    grpcio-tools >= 1.62.1
     invoke >= 1.7.3
-    mypy == 1.8.0
+    mypy == 1.10.0
     nox >= 2022
-    pylint == 2.15.8
+    pylint == 3.1.0
     pyyaml >= 6.0
     types-appdirs >= 1.4.3
     types-invoke >= 1.7.3
     types-protobuf >= 4.21.0
+    wasmtime == 20.0.0
 avatar =
-    pandora-avatar == 0.0.8
-    rootcanal == 1.9.0 ; python_version>='3.10'
+    pandora-avatar == 0.0.9
+    rootcanal == 1.10.0 ; python_version>='3.10'
+pandora =
+    bt-test-interfaces >= 0.0.6
 documentation =
     mkdocs >= 1.4.0
     mkdocs-material >= 8.5.6
diff --git a/tests/bap_test.py b/tests/bap_test.py
index bc223c1..0b6db1a 100644
--- a/tests/bap_test.py
+++ b/tests/bap_test.py
@@ -72,7 +72,7 @@ def test_codec_specific_capabilities() -> None:
     cap = CodecSpecificCapabilities(
         supported_sampling_frequencies=SAMPLE_FREQUENCY,
         supported_frame_durations=FRAME_SURATION,
-        supported_audio_channel_counts=AUDIO_CHANNEL_COUNTS,
+        supported_audio_channel_count=AUDIO_CHANNEL_COUNTS,
         min_octets_per_codec_frame=40,
         max_octets_per_codec_frame=40,
         supported_max_codec_frames_per_sdu=1,
@@ -88,7 +88,7 @@ def test_pac_record() -> None:
     cap = CodecSpecificCapabilities(
         supported_sampling_frequencies=SAMPLE_FREQUENCY,
         supported_frame_durations=FRAME_SURATION,
-        supported_audio_channel_counts=AUDIO_CHANNEL_COUNTS,
+        supported_audio_channel_count=AUDIO_CHANNEL_COUNTS,
         min_octets_per_codec_frame=40,
         max_octets_per_codec_frame=40,
         supported_max_codec_frames_per_sdu=1,
@@ -216,7 +216,7 @@ async def test_pacs():
                         supported_frame_durations=(
                             SupportedFrameDuration.DURATION_10000_US_SUPPORTED
                         ),
-                        supported_audio_channel_counts=[1],
+                        supported_audio_channel_count=[1],
                         min_octets_per_codec_frame=40,
                         max_octets_per_codec_frame=40,
                         supported_max_codec_frames_per_sdu=1,
@@ -232,7 +232,7 @@ async def test_pacs():
                         supported_frame_durations=(
                             SupportedFrameDuration.DURATION_10000_US_SUPPORTED
                         ),
-                        supported_audio_channel_counts=[1],
+                        supported_audio_channel_count=[1],
                         min_octets_per_codec_frame=60,
                         max_octets_per_codec_frame=60,
                         supported_max_codec_frames_per_sdu=1,
diff --git a/tests/core_test.py b/tests/core_test.py
index 6c9d0c3..11afb1c 100644
--- a/tests/core_test.py
+++ b/tests/core_test.py
@@ -17,6 +17,7 @@
 # -----------------------------------------------------------------------------
 from bumble.core import AdvertisingData, UUID, get_dict_key_by_value
 
+
 # -----------------------------------------------------------------------------
 def test_ad_data():
     data = bytes([2, AdvertisingData.TX_POWER_LEVEL, 123])
diff --git a/tests/device_test.py b/tests/device_test.py
index 5d87282..ac0c96b 100644
--- a/tests/device_test.py
+++ b/tests/device_test.py
@@ -16,6 +16,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import functools
 import logging
 import os
 from types import LambdaType
@@ -35,12 +36,14 @@ from bumble.hci import (
     HCI_COMMAND_STATUS_PENDING,
     HCI_CREATE_CONNECTION_COMMAND,
     HCI_SUCCESS,
+    HCI_CONNECTION_FAILED_TO_BE_ESTABLISHED_ERROR,
     Address,
     OwnAddressType,
     HCI_Command_Complete_Event,
     HCI_Command_Status_Event,
     HCI_Connection_Complete_Event,
     HCI_Connection_Request_Event,
+    HCI_Error,
     HCI_Packet,
 )
 from bumble.gatt import (
@@ -52,6 +55,10 @@ from bumble.gatt import (
 
 from .test_utils import TwoDevices, async_barrier
 
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+_TIMEOUT = 0.1
 
 # -----------------------------------------------------------------------------
 # Logging
@@ -214,6 +221,12 @@ async def test_device_connect_parallel():
     d1.host.set_packet_sink(Sink(d1_flow()))
     d2.host.set_packet_sink(Sink(d2_flow()))
 
+    d1_accept_task = asyncio.create_task(d1.accept(peer_address=d0.public_address))
+    d2_accept_task = asyncio.create_task(d2.accept())
+
+    # Ensure that the accept tasks have started.
+    await async_barrier()
+
     [c01, c02, a10, a20] = await asyncio.gather(
         *[
             asyncio.create_task(
@@ -222,8 +235,8 @@ async def test_device_connect_parallel():
             asyncio.create_task(
                 d0.connect(d2.public_address, transport=BT_BR_EDR_TRANSPORT)
             ),
-            asyncio.create_task(d1.accept(peer_address=d0.public_address)),
-            asyncio.create_task(d2.accept()),
+            d1_accept_task,
+            d2_accept_task,
         ]
     )
 
@@ -387,6 +400,29 @@ async def test_get_remote_le_features():
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
+async def test_get_remote_le_features_failed():
+    devices = TwoDevices()
+    await devices.setup_connection()
+
+    def on_hci_le_read_remote_features_complete_event(event):
+        devices[0].host.emit(
+            'le_remote_features_failure',
+            event.connection_handle,
+            HCI_CONNECTION_FAILED_TO_BE_ESTABLISHED_ERROR,
+        )
+
+    devices[0].host.on_hci_le_read_remote_features_complete_event = (
+        on_hci_le_read_remote_features_complete_event
+    )
+
+    with pytest.raises(HCI_Error):
+        await asyncio.wait_for(
+            devices.connections[0].get_remote_le_features(), _TIMEOUT
+        )
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
 async def test_cis():
     devices = TwoDevices()
     await devices.setup_connection()
@@ -434,6 +470,65 @@ async def test_cis():
 
 
 # -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_cis_setup_failure():
+    devices = TwoDevices()
+    await devices.setup_connection()
+
+    cis_requests = asyncio.Queue()
+
+    def on_cis_request(
+        acl_connection: Connection,
+        cis_handle: int,
+        cig_id: int,
+        cis_id: int,
+    ):
+        del acl_connection, cig_id, cis_id
+        cis_requests.put_nowait(cis_handle)
+
+    devices[1].on('cis_request', on_cis_request)
+
+    cis_handles = await devices[0].setup_cig(
+        cig_id=1,
+        cis_id=[2],
+        sdu_interval=(0, 0),
+        framing=0,
+        max_sdu=(0, 0),
+        retransmission_number=0,
+        max_transport_latency=(0, 0),
+    )
+    assert len(cis_handles) == 1
+
+    cis_create_task = asyncio.create_task(
+        devices[0].create_cis(
+            [
+                (cis_handles[0], devices.connections[0].handle),
+            ]
+        )
+    )
+
+    def on_hci_le_cis_established_event(host, event):
+        host.emit(
+            'cis_establishment_failure',
+            event.connection_handle,
+            HCI_CONNECTION_FAILED_TO_BE_ESTABLISHED_ERROR,
+        )
+
+    for device in devices:
+        device.host.on_hci_le_cis_established_event = functools.partial(
+            on_hci_le_cis_established_event, device.host
+        )
+
+    cis_request = await asyncio.wait_for(cis_requests.get(), _TIMEOUT)
+
+    with pytest.raises(HCI_Error):
+        await asyncio.wait_for(devices[1].accept_cis_request(cis_request), _TIMEOUT)
+
+    with pytest.raises(HCI_Error):
+        await asyncio.wait_for(cis_create_task, _TIMEOUT)
+
+
+# -----------------------------------------------------------------------------
 def test_gatt_services_with_gas():
     device = Device(host=Host(None, None))
 
diff --git a/tests/hfp_test.py b/tests/hfp_test.py
index dc28180..83b0d35 100644
--- a/tests/hfp_test.py
+++ b/tests/hfp_test.py
@@ -19,8 +19,9 @@ import asyncio
 import logging
 import os
 import pytest
+import pytest_asyncio
 
-from typing import Tuple
+from typing import Tuple, Optional
 
 from .test_utils import TwoDevices
 from bumble import core
@@ -36,9 +37,93 @@ logger = logging.getLogger(__name__)
 
 
 # -----------------------------------------------------------------------------
+def _default_hf_configuration() -> hfp.HfConfiguration:
+    return hfp.HfConfiguration(
+        supported_hf_features=[
+            hfp.HfFeature.CODEC_NEGOTIATION,
+            hfp.HfFeature.ESCO_S4_SETTINGS_SUPPORTED,
+            hfp.HfFeature.HF_INDICATORS,
+            hfp.HfFeature.ENHANCED_CALL_STATUS,
+            hfp.HfFeature.THREE_WAY_CALLING,
+            hfp.HfFeature.CLI_PRESENTATION_CAPABILITY,
+        ],
+        supported_hf_indicators=[
+            hfp.HfIndicator.ENHANCED_SAFETY,
+            hfp.HfIndicator.BATTERY_LEVEL,
+        ],
+        supported_audio_codecs=[
+            hfp.AudioCodec.CVSD,
+            hfp.AudioCodec.MSBC,
+        ],
+    )
+
+
+# -----------------------------------------------------------------------------
+def _default_hf_sdp_features() -> hfp.HfSdpFeature:
+    return (
+        hfp.HfSdpFeature.WIDE_BAND
+        | hfp.HfSdpFeature.THREE_WAY_CALLING
+        | hfp.HfSdpFeature.CLI_PRESENTATION_CAPABILITY
+    )
+
+
+# -----------------------------------------------------------------------------
+def _default_ag_configuration() -> hfp.AgConfiguration:
+    return hfp.AgConfiguration(
+        supported_ag_features=[
+            hfp.AgFeature.HF_INDICATORS,
+            hfp.AgFeature.IN_BAND_RING_TONE_CAPABILITY,
+            hfp.AgFeature.REJECT_CALL,
+            hfp.AgFeature.CODEC_NEGOTIATION,
+            hfp.AgFeature.ESCO_S4_SETTINGS_SUPPORTED,
+            hfp.AgFeature.ENHANCED_CALL_STATUS,
+            hfp.AgFeature.THREE_WAY_CALLING,
+        ],
+        supported_ag_indicators=[
+            hfp.AgIndicatorState.call(),
+            hfp.AgIndicatorState.service(),
+            hfp.AgIndicatorState.callsetup(),
+            hfp.AgIndicatorState.callsetup(),
+            hfp.AgIndicatorState.signal(),
+            hfp.AgIndicatorState.roam(),
+            hfp.AgIndicatorState.battchg(),
+        ],
+        supported_hf_indicators=[
+            hfp.HfIndicator.ENHANCED_SAFETY,
+            hfp.HfIndicator.BATTERY_LEVEL,
+        ],
+        supported_ag_call_hold_operations=[
+            hfp.CallHoldOperation.ADD_HELD_CALL,
+            hfp.CallHoldOperation.HOLD_ALL_ACTIVE_CALLS,
+            hfp.CallHoldOperation.HOLD_ALL_CALLS_EXCEPT,
+            hfp.CallHoldOperation.RELEASE_ALL_ACTIVE_CALLS,
+            hfp.CallHoldOperation.RELEASE_ALL_HELD_CALLS,
+            hfp.CallHoldOperation.RELEASE_SPECIFIC_CALL,
+            hfp.CallHoldOperation.CONNECT_TWO_CALLS,
+        ],
+        supported_audio_codecs=[hfp.AudioCodec.CVSD, hfp.AudioCodec.MSBC],
+    )
+
+
+# -----------------------------------------------------------------------------
+def _default_ag_sdp_features() -> hfp.AgSdpFeature:
+    return (
+        hfp.AgSdpFeature.WIDE_BAND
+        | hfp.AgSdpFeature.IN_BAND_RING_TONE_CAPABILITY
+        | hfp.AgSdpFeature.THREE_WAY_CALLING
+    )
+
+
+# -----------------------------------------------------------------------------
 async def make_hfp_connections(
-    hf_config: hfp.Configuration,
-) -> Tuple[hfp.HfProtocol, hfp.HfpProtocol]:
+    hf_config: Optional[hfp.HfConfiguration] = None,
+    ag_config: Optional[hfp.AgConfiguration] = None,
+):
+    if not hf_config:
+        hf_config = _default_hf_configuration()
+    if not ag_config:
+        ag_config = _default_ag_configuration()
+
     # Setup devices
     devices = TwoDevices()
     await devices.setup_connection()
@@ -55,38 +140,371 @@ async def make_hfp_connections(
 
     # Setup HFP connection
     hf = hfp.HfProtocol(client_dlc, hf_config)
-    ag = hfp.HfpProtocol(server_dlc)
-    return hf, ag
+    ag = hfp.AgProtocol(server_dlc, ag_config)
+
+    await hf.initiate_slc()
+    return (hf, ag)
 
 
 # -----------------------------------------------------------------------------
+@pytest_asyncio.fixture
+async def hfp_connections():
+    hf, ag = await make_hfp_connections()
+    hf_loop_task = asyncio.create_task(hf.run())
+
+    try:
+        yield (hf, ag)
+    finally:
+        # Close the coroutine.
+        hf.unsolicited_queue.put_nowait(None)
+        await hf_loop_task
 
 
+# -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_slc():
-    hf_config = hfp.Configuration(
-        supported_hf_features=[], supported_hf_indicators=[], supported_audio_codecs=[]
-    )
-    hf, ag = await make_hfp_connections(hf_config)
-
-    async def ag_loop():
-        while line := await ag.next_line():
-            if line.startswith('AT+BRSF'):
-                ag.send_response_line('+BRSF: 0')
-            elif line.startswith('AT+CIND=?'):
-                ag.send_response_line(
-                    '+CIND: ("call",(0,1)),("callsetup",(0-3)),("service",(0-1)),'
-                    '("signal",(0-5)),("roam",(0,1)),("battchg",(0-5)),'
-                    '("callheld",(0-2))'
+async def test_slc_with_minimal_features():
+    hf, ag = await make_hfp_connections(
+        hfp.HfConfiguration(
+            supported_audio_codecs=[],
+            supported_hf_features=[],
+            supported_hf_indicators=[],
+        ),
+        hfp.AgConfiguration(
+            supported_ag_call_hold_operations=[],
+            supported_ag_features=[],
+            supported_ag_indicators=[
+                hfp.AgIndicatorState(
+                    indicator=hfp.AgIndicator.CALL,
+                    supported_values={0, 1},
+                    current_status=0,
                 )
-            elif line.startswith('AT+CIND?'):
-                ag.send_response_line('+CIND: 0,0,1,4,1,5,0')
-            ag.send_response_line('OK')
+            ],
+            supported_hf_indicators=[],
+            supported_audio_codecs=[],
+        ),
+    )
 
-    ag_task = asyncio.create_task(ag_loop())
+    assert hf.supported_ag_features == ag.supported_ag_features
+    assert hf.supported_hf_features == ag.supported_hf_features
+    assert hf.supported_ag_call_hold_operations == ag.supported_ag_call_hold_operations
+    for a, b in zip(hf.ag_indicators, ag.ag_indicators):
+        assert a.indicator == b.indicator
+        assert a.current_status == b.current_status
 
-    await hf.initiate_slc()
-    ag_task.cancel()
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_slc(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+
+    assert hf.supported_ag_features == ag.supported_ag_features
+    assert hf.supported_hf_features == ag.supported_hf_features
+    assert hf.supported_ag_call_hold_operations == ag.supported_ag_call_hold_operations
+    for a, b in zip(hf.ag_indicators, ag.ag_indicators):
+        assert a.indicator == b.indicator
+        assert a.current_status == b.current_status
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_ag_indicator(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+
+    future = asyncio.get_running_loop().create_future()
+    hf.on('ag_indicator', future.set_result)
+
+    ag.update_ag_indicator(hfp.AgIndicator.CALL, 1)
+
+    indicator: hfp.AgIndicatorState = await future
+    assert indicator.current_status == 1
+    assert indicator.indicator == hfp.AgIndicator.CALL
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_hf_indicator(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+
+    future = asyncio.get_running_loop().create_future()
+    ag.on('hf_indicator', future.set_result)
+
+    await hf.execute_command('AT+BIEV=2,100')
+
+    indicator: hfp.HfIndicatorState = await future
+    assert indicator.current_status == 100
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_codec_negotiation(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+
+    futures = [
+        asyncio.get_running_loop().create_future(),
+        asyncio.get_running_loop().create_future(),
+    ]
+    hf.on('codec_negotiation', futures[0].set_result)
+    ag.on('codec_negotiation', futures[1].set_result)
+    await ag.negotiate_codec(hfp.AudioCodec.MSBC)
+
+    assert await futures[0] == await futures[1]
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_dial(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+    NUMBER = 'ATD123456789'
+
+    future = asyncio.get_running_loop().create_future()
+    ag.on('dial', future.set_result)
+    await hf.execute_command(f'ATD{NUMBER}')
+
+    number: str = await future
+    assert number == NUMBER
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_answer(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+
+    future = asyncio.get_running_loop().create_future()
+    ag.on('answer', lambda: future.set_result(None))
+    await hf.answer_incoming_call()
+
+    await future
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_reject_incoming_call(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+
+    future = asyncio.get_running_loop().create_future()
+    ag.on('hang_up', lambda: future.set_result(None))
+    await hf.reject_incoming_call()
+
+    await future
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_terminate_call(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+
+    future = asyncio.get_running_loop().create_future()
+    ag.on('hang_up', lambda: future.set_result(None))
+    await hf.terminate_call()
+
+    await future
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_query_calls_without_calls(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+
+    assert await hf.query_current_calls() == []
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_query_calls_with_calls(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+    ag.calls.append(
+        hfp.CallInfo(
+            index=1,
+            direction=hfp.CallInfoDirection.MOBILE_ORIGINATED_CALL,
+            status=hfp.CallInfoStatus.ACTIVE,
+            mode=hfp.CallInfoMode.VOICE,
+            multi_party=hfp.CallInfoMultiParty.NOT_IN_CONFERENCE,
+            number='123456789',
+        )
+    )
+
+    assert await hf.query_current_calls() == ag.calls
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "operation,",
+    (
+        hfp.CallHoldOperation.RELEASE_ALL_HELD_CALLS,
+        hfp.CallHoldOperation.RELEASE_ALL_ACTIVE_CALLS,
+        hfp.CallHoldOperation.HOLD_ALL_ACTIVE_CALLS,
+        hfp.CallHoldOperation.ADD_HELD_CALL,
+        hfp.CallHoldOperation.CONNECT_TWO_CALLS,
+    ),
+)
+async def test_hold_call_without_call_index(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol],
+    operation: hfp.CallHoldOperation,
+):
+    hf, ag = hfp_connections
+    call_hold_future = asyncio.get_running_loop().create_future()
+    ag.on("call_hold", lambda op, index: call_hold_future.set_result((op, index)))
+
+    await hf.execute_command(f"AT+CHLD={operation.value}")
+
+    assert (await call_hold_future) == (operation, None)
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "operation,",
+    (
+        hfp.CallHoldOperation.RELEASE_SPECIFIC_CALL,
+        hfp.CallHoldOperation.HOLD_ALL_CALLS_EXCEPT,
+    ),
+)
+async def test_hold_call_with_call_index(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol],
+    operation: hfp.CallHoldOperation,
+):
+    hf, ag = hfp_connections
+    call_hold_future = asyncio.get_running_loop().create_future()
+    ag.on("call_hold", lambda op, index: call_hold_future.set_result((op, index)))
+    ag.calls.append(
+        hfp.CallInfo(
+            index=1,
+            direction=hfp.CallInfoDirection.MOBILE_ORIGINATED_CALL,
+            status=hfp.CallInfoStatus.ACTIVE,
+            mode=hfp.CallInfoMode.VOICE,
+            multi_party=hfp.CallInfoMultiParty.NOT_IN_CONFERENCE,
+            number='123456789',
+        )
+    )
+
+    await hf.execute_command(f"AT+CHLD={operation.value.replace('x', '1')}")
+
+    assert (await call_hold_future) == (operation, 1)
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_ring(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+    ring_future = asyncio.get_running_loop().create_future()
+    hf.on("ring", lambda: ring_future.set_result(None))
+
+    ag.send_ring()
+
+    await ring_future
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_speaker_volume(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+    speaker_volume_future = asyncio.get_running_loop().create_future()
+    hf.on("speaker_volume", speaker_volume_future.set_result)
+
+    ag.set_speaker_volume(10)
+
+    assert await speaker_volume_future == 10
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_microphone_volume(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+    microphone_volume_future = asyncio.get_running_loop().create_future()
+    hf.on("microphone_volume", microphone_volume_future.set_result)
+
+    ag.set_microphone_volume(10)
+
+    assert await microphone_volume_future == 10
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_cli_notification(hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]):
+    hf, ag = hfp_connections
+    cli_notification_future = asyncio.get_running_loop().create_future()
+    hf.on("cli_notification", cli_notification_future.set_result)
+
+    ag.send_cli_notification(
+        hfp.CallLineIdentification(number="\"123456789\"", type=129, alpha="\"Bumble\"")
+    )
+
+    assert await cli_notification_future == hfp.CallLineIdentification(
+        number="123456789", type=129, alpha="Bumble", subaddr="", satype=None
+    )
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_voice_recognition_from_hf(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+    voice_recognition_future = asyncio.get_running_loop().create_future()
+    ag.on("voice_recognition", voice_recognition_future.set_result)
+
+    await hf.execute_command("AT+BVRA=1")
+
+    assert await voice_recognition_future == hfp.VoiceRecognitionState.ENABLE
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_voice_recognition_from_ag(
+    hfp_connections: Tuple[hfp.HfProtocol, hfp.AgProtocol]
+):
+    hf, ag = hfp_connections
+    voice_recognition_future = asyncio.get_running_loop().create_future()
+    hf.on("voice_recognition", voice_recognition_future.set_result)
+
+    ag.send_response("+BVRA: 1")
+
+    assert await voice_recognition_future == hfp.VoiceRecognitionState.ENABLE
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_hf_sdp_record():
+    devices = TwoDevices()
+    await devices.setup_connection()
+
+    devices[0].sdp_service_records[1] = hfp.make_hf_sdp_records(
+        1, 2, _default_hf_configuration(), hfp.ProfileVersion.V1_8
+    )
+
+    assert await hfp.find_hf_sdp_record(devices.connections[1]) == (
+        2,
+        hfp.ProfileVersion.V1_8,
+        _default_hf_sdp_features(),
+    )
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_ag_sdp_record():
+    devices = TwoDevices()
+    await devices.setup_connection()
+
+    devices[0].sdp_service_records[1] = hfp.make_ag_sdp_records(
+        1, 2, _default_ag_configuration(), hfp.ProfileVersion.V1_8
+    )
+
+    assert await hfp.find_ag_sdp_record(devices.connections[1]) == (
+        2,
+        hfp.ProfileVersion.V1_8,
+        _default_ag_sdp_features(),
+    )
 
 
 # -----------------------------------------------------------------------------
diff --git a/tests/rfcomm_test.py b/tests/rfcomm_test.py
index 4ce4d11..5146c8b 100644
--- a/tests/rfcomm_test.py
+++ b/tests/rfcomm_test.py
@@ -32,6 +32,8 @@ from bumble.rfcomm import (
     RFCOMM_PSM,
 )
 
+_TIMEOUT = 0.1
+
 
 # -----------------------------------------------------------------------------
 def basic_frame_check(x):
@@ -60,7 +62,7 @@ def test_frames():
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_basic_connection() -> None:
+async def test_connection_and_disconnection() -> None:
     devices = test_utils.TwoDevices()
     await devices.setup_connection()
 
@@ -81,6 +83,34 @@ async def test_basic_connection() -> None:
     dlcs[1].write(b'Lorem ipsum dolor sit amet')
     assert await queues[0].get() == b'Lorem ipsum dolor sit amet'
 
+    closed = asyncio.Event()
+    dlcs[1].on('close', closed.set)
+    await dlcs[1].disconnect()
+    await closed.wait()
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_receive_pdu_before_open_dlc_returns() -> None:
+    devices = await test_utils.TwoDevices.create_with_connection()
+    DATA = b'123'
+
+    accept_future: asyncio.Future[DLC] = asyncio.get_running_loop().create_future()
+    channel = Server(devices[0]).listen(acceptor=accept_future.set_result)
+
+    assert devices.connections[1]
+    multiplexer = await Client(devices.connections[1]).start()
+    open_dlc_task = asyncio.create_task(multiplexer.open_dlc(channel))
+
+    dlc_responder = await accept_future
+    dlc_responder.write(DATA)
+
+    dlc_initiator = await open_dlc_task
+    dlc_initiator_queue = asyncio.Queue()  # type: ignore[var-annotated]
+    dlc_initiator.sink = dlc_initiator_queue.put_nowait
+
+    assert await asyncio.wait_for(dlc_initiator_queue.get(), timeout=_TIMEOUT) == DATA
+
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
diff --git a/tests/self_test.py b/tests/self_test.py
index 259de02..5c68ea0 100644
--- a/tests/self_test.py
+++ b/tests/self_test.py
@@ -316,13 +316,13 @@ async def _test_self_smp_with_configs(pairing_config1, pairing_config2):
 
     # Set up the pairing configs
     if pairing_config1:
-        two_devices.devices[
-            0
-        ].pairing_config_factory = lambda connection: pairing_config1
+        two_devices.devices[0].pairing_config_factory = (
+            lambda connection: pairing_config1
+        )
     if pairing_config2:
-        two_devices.devices[
-            1
-        ].pairing_config_factory = lambda connection: pairing_config2
+        two_devices.devices[1].pairing_config_factory = (
+            lambda connection: pairing_config2
+        )
 
     # Pair
     await two_devices.devices[0].pair(connection)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index d193d6e..1f0b4f3 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -16,7 +16,8 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
-from typing import List, Optional
+from typing import List, Optional, Type
+from typing_extensions import Self
 
 from bumble.controller import Controller
 from bumble.link import LocalLink
@@ -81,6 +82,12 @@ class TwoDevices:
     def __getitem__(self, index: int) -> Device:
         return self.devices[index]
 
+    @classmethod
+    async def create_with_connection(cls: Type[Self]) -> Self:
+        devices = cls()
+        await devices.setup_connection()
+        return devices
+
 
 # -----------------------------------------------------------------------------
 async def async_barrier():
diff --git a/tests/transport_tcp_server_test.py b/tests/transport_tcp_server_test.py
new file mode 100644
index 0000000..a5f015d
--- /dev/null
+++ b/tests/transport_tcp_server_test.py
@@ -0,0 +1,64 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import asyncio
+import os
+import pytest
+import socket
+import unittest
+from unittest.mock import ANY, patch
+
+from bumble.transport.tcp_server import (
+    open_tcp_server_transport,
+    open_tcp_server_transport_with_socket,
+)
+
+
+class OpenTcpServerTransportTests(unittest.TestCase):
+    def setUp(self):
+        self.patcher = patch('bumble.transport.tcp_server._create_server')
+        self.mock_create_server = self.patcher.start()
+
+    def tearDown(self):
+        self.patcher.stop()
+
+    def test_open_with_spec(self):
+        asyncio.run(open_tcp_server_transport('localhost:32100'))
+        self.mock_create_server.assert_awaited_once_with(
+            ANY, host='localhost', port=32100
+        )
+
+    def test_open_with_port_only_spec(self):
+        asyncio.run(open_tcp_server_transport('_:32100'))
+        self.mock_create_server.assert_awaited_once_with(ANY, host=None, port=32100)
+
+    def test_open_with_socket(self):
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            asyncio.run(open_tcp_server_transport_with_socket(sock=sock))
+        self.mock_create_server.assert_awaited_once_with(ANY, sock=sock)
+
+
+@pytest.mark.skipif(
+    not os.environ.get('PYTEST_NOSKIP', 0),
+    reason='''\
+Not hermetic. Should only run manually with
+  $ PYTEST_NOSKIP=1 pytest tests
+''',
+)
+def test_open_with_real_socket():
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+        sock.bind(('localhost', 0))
+        port = sock.getsockname()[1]
+        assert port != 0
+        asyncio.run(open_tcp_server_transport_with_socket(sock=sock))
diff --git a/tools/rtk_fw_download.py b/tools/rtk_fw_download.py
index 89c49b2..74c783b 100644
--- a/tools/rtk_fw_download.py
+++ b/tools/rtk_fw_download.py
@@ -49,6 +49,7 @@ LINUX_FROM_SCRATCH_SOURCE = (
     False,
 )
 
+
 # -----------------------------------------------------------------------------
 # Functions
 # -----------------------------------------------------------------------------
@@ -111,7 +112,7 @@ def main(output_dir, source, single, force, parse):
             for driver_info in rtk.Driver.DRIVER_INFOS
         ]
 
-    for (fw_name, config_name, config_needed) in images:
+    for fw_name, config_name, config_needed in images:
         print(color("---", "yellow"))
         fw_image_out = output_dir / fw_name
         if not force and fw_image_out.exists():
diff --git a/web/bumble.js b/web/bumble.js
index cb807eb..c554bc2 100644
--- a/web/bumble.js
+++ b/web/bumble.js
@@ -24,6 +24,11 @@ class PacketSource {
 }
 
 class PacketSink {
+    constructor() {
+        this.queue = [];
+        this.isProcessing = false;
+    }
+
     on_packet(packet) {
         if (!this.writer) {
             return;
@@ -31,11 +36,24 @@ class PacketSink {
         const buffer = packet.toJs({create_proxies : false});
         packet.destroy();
         //console.log(`HCI[host->controller]: ${bufferToHex(buffer)}`);
-        // TODO: create an async queue here instead of blindly calling write without awaiting
-        this.writer(buffer);
+        this.queue.push(buffer);
+        this.processQueue();
+    }
+
+    async processQueue() {
+        if (this.isProcessing) {
+            return;
+        }
+        this.isProcessing = true;
+        while (this.queue.length > 0) {
+            const buffer = this.queue.shift();
+            await this.writer(buffer);
+        }
+        this.isProcessing = false;
     }
 }
 
+
 class LogEvent extends Event {
     constructor(message) {
         super('log');
@@ -185,4 +203,4 @@ export async function setupSimpleApp(appUrl, bumbleControls, log) {
     bumbleControls.onBumbleLoaded();
 
     return app;
-}
\ No newline at end of file
+}