AAP runs on top of L2CAP, with a PSM of 0x1001 or 4097.
This packet is necessary to establish a connection with the AirPods. Or else, the AirPods will not respond to any packets.
00 00 04 00 01 00 02 00 00 00 00 00 00 00 00 00
may work for airpods 4 anc also, not tested
Since apple likes to wall off some features behind specific OS versions, and apple silicon devices, some packets are necessary to enable these features.
I captured the following packet only accidentally, because Apple being Apple decided to hide this and the handshake from packetlogger, but sometimes it shows up.
Captured using PacketLogger on an Intel Mac running macOS Sequoia 15.0.1
04 00 04 00 4d 00 ff 00 00 00 00 00 00 00
This packet enables conversational awareness when playing audio. (CA works without this packet only when no audio is playing)
It also enables the Adaptive Transparency feature. (We can set Adaptive Transparency, but it doesn't respond with the same packet See Noise Cancellation)
This packet is necessary to receive notifications from the AirPods like ear detection, noise control mode, conversational awareness, battery status, etc.
Captured using PacketLogger on an Intel Mac running macOS Sequoia 15.0.1
04 00 04 00 0F 00 FF FF FE FF
This packet also works.
04 00 04 00 0F 00 FF FF FF FF
AirPods occasionally send battery status packets. The packet format is as follows:
04 00 04 00 04 00 [battery count] ([component] 01 [level] [status] 01) times the battery count
| Components | Byte value |
|---|---|
| Case | 08 |
| Left | 04 |
| Right | 02 |
| Status | Byte value |
|---|---|
| Unknown | 00 |
| Charging | 01 |
| Discharging | 02 |
| Disconnected | 04 |
Example packet from AirPods Pro 2
04 00 04 00 04 00 03 02 01 64 02 01 04 01 63 01 01 08 01 11 02 01
| Byte | Interpretation |
|---|---|
| 7th byte | Battery Count - 3 |
| 8th byte | Battery type - Left |
| 9th byte | Spacer, value = 0x01 |
| 10th byte | Battery level 100% |
| 11th byte | Battery status - Discharging |
| 12th byte | Battery component end value = 0x01 |
| 13th byte | Battery type - Right |
| 14th byte | Spacer, value = 0x01 |
| 15th byte | Battery level 99% |
| 16th byte | Battery status - Charging |
| 17th byte | Battery component end value = 0x01 |
| 18th byte | Battery type - Case |
| 19th byte | Spacer, value = 0x01 |
| 20th byte | Battery level 17% |
| 21st byte | Battery status - Discharging |
| 22nd byte | Battery component end value = 0x01 |
The AirPods Pro 2 send noise control packets when the noise control mode is changed (either by a stem long press or by the connected device, see Changing noise control). The packet format is as follows:
04 00 04 00 09 00 0D [mode] 00 00 00
| Noise Control Mode | Byte value |
|---|---|
| Off | 01 |
| Noise Cancellation | 02 |
| Transparency | 03 |
| Adaptive Transparency | 04 |
AirPods send ear detection packets when the ear detection status changes. The packet format is as follows:
04 00 04 00 06 00 [primary pod] [secondary pod]
If primary is removed, mic will be changed and the secondary will be the new primary, so the primary will be the one in the ear, and the packet will be sent again.
| Pod Status | Byte value |
|---|---|
| In Ear | 00 |
| Out of Ear | 01 |
| In Case | 02 |
AirPods send conversational awareness packets when the person wearing them start speaking. The packet format is as follows:
04 00 04 00 4B 00 02 00 01 [level]
| Level Byte Value | Meaning |
|---|---|
| 01/02 | Person Started Speaking; greatly reduce volume |
| 03 | Person Stopped Speaking; increase volume back to normal |
| Intermediate values | Intermediate volume levels |
| 08/09 | Normal Volume |
We can send a packet to change the noise control mode. The packet format is as follows:
04 00 04 00 09 00 0D [mode] 00 00 00
| Noise Control Mode | Byte value |
|---|---|
| Off | 01 |
| Noise Cancellation | 02 |
| Transparency | 03 |
| Adaptive Transparency | 04 |
The airpods will respond with the same packet after the mode has been changed.
But if your airpods support Adaptive Transparency, and you haven't sent that special packet to enable it, the airpods will respond with the same packet but with a different mode (like 0x02).
We can send a packet to rename the AirPods. The packet format is as follows:
04 00 04 00 1A 00 01 [size] 00 [name]
This feature is only for cases with a speaker, i.e. the AirPods Pro 2 and the new AirPods 4. Tested only on AirPods Pro 2
We can send a packet to toggle if sounds should be played when the case is connected to a charger. The packet format is as follows:
12 3A 00 01 00 08 [setting]
| Byte Value | Sound |
|---|---|
| 00 | On |
| 01 | Off |
This feature is only for AirPods Pro 2 and the new AirPods 4 with ANC. Tested only on AirPods Pro 2
We can send a packet to toggle Conversational Awareness. If enabled, the AirPods will switch to Transparency mode when the person wearing them starts speaking (and sends packet for notifying the device to reduce volume). The packet format is as follows:
04 00 04 00 09 00 28 [setting] 00 00 00
| Byte Value | C.A. |
|---|---|
| 01 | On |
| 02 | Off |
This feature is only for AirPods Pro 2 and the new AirPods 4 with ANC. Tested only on AirPods Pro 2
The new firmware 7A305 for app2 has a new feature called Adaptive Audio Noise. This allows us to control how much noise is passed through the AirPods when the noise control mode is set to Adaptive. The packet format is as follows:
04 00 04 00 09 00 2E [level] 00 00 00
The level can be any value between 0 and 100, 0 to allow maximum noise (i.e. minimum noise filtering), and 100 to filter out more noise.
This feature is only effective when the noise control mode is set to Adaptive.
I find it quite funny how I have greater control over the noise control on the AirPods on non-Apple devices than on Apple devices, becuase on Apple Devices, there are just 3 options More Noise (0), Midway through (50), and Less Noise (100), but here I can set any value between 0 and 100.
04 00 04 00 53 00 84 00 02 02 [Phone] [Media]
[EQ1][EQ2][EQ3][EQ4][EQ5][EQ6][EQ7][EQ8]
duplicated thrice for some reason
| Data | Type | Value range |
|---|---|---|
| Phone | Decimal | 1 (Enabled) or 2 (Disabled) |
| Media | Decimal | 1 (Enabled) or 2 (Disabled) |
| EQ | Little Endian | 0 to 100 |
52 18 00
For left bud
[Enabled]
[EQ1][EQ2][EQ3][EQ4][EQ5][EQ6][EQ7][EQ8]
[Amplification]
[Tone]
[Conversation Boost]
[Ambient Noise Reduction]
00 0080 3F
<same for the right bud>
All values are formatted as Little Endian from float values.
| Data | Type | Value range |
|---|---|---|
| Enabled | Little Endian | 0 or 1 |
| EQ | Little Endian | 0 to 100 |
| Amplification | Little Endian | -1 to 1 |
| Tone | Little Endian | -1 to 1 |
| Conversation Boost | Little Endian | 0 or 1 |
Important
Also send the Headphone Accomodation after this.
I have noted all the packets sent to configure what the press and hold of the steam should do. The packets sent are specific to the current state. And are probably overwritten everytime the AirPods are connected to a new (apple) device that is not synced with icloud (i think)... So, for non-Apple device too, the configuration needs to be stored and overwritten everytime the AirPods are connected to the device. That is the only way to keep the configuration.
This is also the only way to control the configuration as the previous state needs to be known, and then the new state can be set.
The packets sent (based on the previous states) are as follows:
Toggling Adaptive
04 00 04 00 09 00 1A 0B 00 00 00 - Turns on Adaptive from O and ANC
04 00 04 00 09 00 1A 0D 00 00 00 - Turns on Adaptive from O and T
04 00 04 00 09 00 1A 0E 00 00 00 - Turns on Adaptive from T and ANC
04 00 04 00 09 00 1A 0F 00 00 00 - Turns on Adaptive from O, T, ANC
04 00 04 00 09 00 1A 03 00 00 00 - Turns off Adaptive from O and ANC (and Adaptive)
04 00 04 00 09 00 1A 05 00 00 00 - Turns off Adaptive from O and T (and Adaptive)
04 00 04 00 09 00 1A 06 00 00 00 - Turns off Adaptive from T and ANC (and Adaptive)
04 00 04 00 09 00 1A 07 00 00 00 - Turns off Adaptive from O, T, ANC (and Adaptive)
Toggling Transparency
04 00 04 00 09 00 1A 07 00 00 00 - Turns on Transparency from O and ANC
04 00 04 00 09 00 1A 0D 00 00 00 - Turns on Transparency from O and Adaptive
04 00 04 00 09 00 1A 0E 00 00 00 - Turns on Transparency from Adaptive, and ANC
04 00 04 00 09 00 1A 0F 00 00 00 - Turns on Transparency from O and Adaptive and ANC
04 00 04 00 09 00 1A 03 00 00 00 - Turns off Transparency from O and ANC (and Transparency)
04 00 04 00 09 00 1A 09 00 00 00 - Turns off Transparency from O and Adaptive (and Transparency)
04 00 04 00 09 00 1A 0A 00 00 00 - Turns off Transparency from Adaptive, and ANC (and Transparency)
04 00 04 00 09 00 1A 0B 00 00 00 - Turns off Transparency from O and Adaptive and ANC (and Transparency)
Toggling ANC
04 00 04 00 09 00 1A 07 00 00 00 - Turns on ANC from O, and Transparency
04 00 04 00 09 00 1A 0B 00 00 00 - Turns on ANC from O, and Adaptive
04 00 04 00 09 00 1A 0E 00 00 00 - Turns on ANC from Adaptive, and Transparency
04 00 04 00 09 00 1A 0F 00 00 00 - Turns on ANC from O and Adaptive and Transparency
04 00 04 00 09 00 1A 05 00 00 00 - Turns off ANC from O and Transparency (and ANC)
04 00 04 00 09 00 1A 09 00 00 00 - Turns off ANC from O and Adaptive (and ANC)
04 00 04 00 09 00 1A 0C 00 00 00 - Turns off ANC from Adaptive, and Transparency (and ANC)
04 00 04 00 09 00 1A 0D 00 00 00 - Turns off ANC from O and Adaptive and Transparency (and ANC)
Toggling O
04 00 04 00 09 00 1A 07 00 00 00 - Turns on O from Transparency, and ANC
04 00 04 00 09 00 1A 0B 00 00 00 - Turns on O from Adaptive, and ANC
04 00 04 00 09 00 1A 0D 00 00 00 - Turns on O from Transparency, and Adaptive
04 00 04 00 09 00 1A 0F 00 00 00 - Turns on O from Transparency, and Adaptive, and ANC
04 00 04 00 09 00 1A 06 00 00 00 - Turns off O from Transparency, and ANC (and O)
04 00 04 00 09 00 1A 0A 00 00 00 - Turns off O from Adaptive, and ANC (and O)
04 00 04 00 09 00 1A 0C 00 00 00 - Turns off O from Transparency, and Adaptive (and O)
04 00 04 00 09 00 1A 0E 00 00 00 - Turns off O from Transparency, and Adaptive, and ANC (and O)
i do hate apple for not hardcoding these, like there are literally only 4^2 - ${\binom{4}{1}}$ - $\binom{4}{2}$
<!-- 04 00 04 00 17 00 00 00 10 00 11 00 08 7C 10 02 42 0B 08 4E 10 02 1A 05 01 40 9C 00 00 -->
OR
04 00 04 00 17 00 00 00 10 00 10 00 08 A1 02 42 0B 08 0E 10 02 1A 05 01 40 9C 00 00
Example packet
04 00 04 00 17 00 00 00 10 00 43 00 08 ec 07 10 01 1a 3c 0e 00 01 90 95 5d af 86 19 00 00 03 04 43 94 04 9e 6b 01 00 00 00 d5 a2 06 13 eb 13 03 00 f0 ff 01 00 67 83 67 83 67 83 fe ff fd ff 07 00 b3 01 9c 03 65 00 48 74 2c 37 fd 1e 00 00
04 00 04 00 17 00 00 00 10 00 11 00 08 7E 10 02 42 0B 08 4E 10 02 1A 05 01 00 00 00 00
AirPods like Normal (ALN) - Bringing Apple-only features to Linux and Android for seamless AirPods functionality! Copyright (C) 2024 Kavish Devar
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