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> **Warning:** **DO NOT PUBLISH** until proofreading is complete. http://b/533228945

Version: 2.0  

Last updated: 2026-09-28

## Overview

This document describes the requirements a ChromeOS Compatible USB speakermic
meets. This specification is not for WWCB products, nor for a product designed
and certified together with a Chromebook.

A single peripheral type specifies a subset of Audio modules that combine to
make the spec for that peripheral. This mapping is provided in the [Modular spec
matrix](https://developers.google.com/chromeos/peripherals/modules/cc-spec-module-matrix).

The peripheral specification assembles using the text in this document specific
to the peripheral, plus the relevant portions in each of the designated modules.


### Minimum and Additional Requirements

This specification document is divided into two sections:

1. **Minimum** requirements describe the criteria for a peripheral category to be compatible.
2. **Additional** requirements describe the criteria for certification.

Use these navigation buttons to show only the minimum or both the minimum
and additional specification, respectively.
<button value="min">Minimum</button> <button value="add" default="">Minimum and Additional</button>

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## Legend

| Product Verb | Development Action |
|---|---|
| "MUST" | Mandatory product requirement |
| "SHOULD" | Optional recommendation |
| "MAY" | Nice to have |

## MINIMUM REQUIREMENTS

This document describes the requirements a ChromeOS Compatible USB and/or Bluetooth
speakermic meets. This specification is not for WWCB products, nor for a
product designed and certified together with a Chromebook.

### Generic peripheral Specifications

- The peripheral MUST meet the [minimum requirements](https://developers.google.com/chromeos/peripherals/cc-generic-peripheral-v2#minimum-requirements) defined in the Generic peripheral specifications.

## USB Audio Specifications

### MINIMUM REQUIREMENTS

#### Hardware

##### Firmware

- Peripheral MUST be declared as an audio device with a correct audio interface (0x01) descriptor.
  - There MUST be one corresponding descriptor for both input and output terminal.
    - It is recommended to report the USB Audio Class (UAC) terminal type:
      - Headset [(0x0402)](https://www.usb.org/sites/default/files/termt10.pdf)
      - SpeakerPhone [(0x0403-0x0405)](https://www.usb.org/sites/default/files/termt10.pdf)
- If it has any button, it MUST be declared as an HID.

#### Software

##### Format


Refer to the [Audio Format](https://developers.google.com/chromeos/peripherals/cc-speakermic-usb-v2#audio_format) section.

##### HID Codes

- For each HID event, it can only transmit one event at a time.
- The correct event code and corresponding event code MUST be received when the button is pressed.
- If there is any interface designed to provide peripheral functionalities, the USB peripheral MUST support emitting or receiving the corresponding HID events according to [USB.org HID specification](https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf).

##### Jack Detection

- If the USB device supports audio jack detection, it MUST declare support for
  USB Audio Class (UAC) in either of the following:

  - [UAC1](https://www.usb.org/document-library/audio-device-class-spec-basic-audio-devices-v10-and-adopters-agreement)
  - [UAC2](https://www.usb.org/document-library/audio-devices-rev-20-and-adopters-agreement)
  - [UAC3](https://www.usb.org/document-library/usb-audio-devices-rev-30-and-adopters-agreement)

### ADDITIONAL REQUIREMENTS

Along with the **Minimum** requirements, a peripheral MUST meet the following
requirements to achieve certification:

- None


## Audio Format

### MINIMUM REQUIREMENTS

|   | Playback | Recording |
| Sample rate | ≥ 16 kHz | ≥ 16 kHz |
| Format | S16_LE | S16_LE |
|---|---|---|

- The channel number and configuration MUST be correct.
- All sampling rates the peripheral declares supported MUST work correctly.
  - The deviation between measured rate and sampling rate MUST be ≤ 0.1%.
  - The standard error for linear regression of measured rate MUST be \< 30.
- The device MUST support playback or capture under different sample rates it
  asserts to support. Otherwise, it requires the OS to add a specific
  configuration file to prevent it on the system side.

  For example: play audio under 44.1 kHz but capture voice under 48 kHz
  simultaneously.

### ADDITIONAL REQUIREMENTS

Along with the **Minimum** requirements, a peripheral MUST meet the following
requirements to achieve certification:

- None

## Audio Quality

### MINIMUM REQUIREMENTS

#### Capture Path - Mute

- If there is any interface for users to mute the audio device, it MUST:
  - Maintain the mute state in a way that is not affected by:
    - Opening and closing the device.
    - Switching to another input device.

### ADDITIONAL REQUIREMENTS

Along with the **Minimum** requirements, a peripheral MUST meet the following
requirements to achieve certification:

#### Playback Path - Loudness

- **\[Mandatory\]** The device MUST comply with EN50332 standards.

#### Capture Path - Mute

- **\[Mandatory\]** If there is any interface for users to mute the audio device, it MUST:
  - Mute the device such that all recorded samples are zeros or within the range of \\((level_{max} - level_{min}) \\le 0.0028 \\text{ dBFS}\\).
    - If the device cannot meet the requirements, then the device SHOULD have a button to mute.
    - The mute button on the device SHOULD trigger the system mute (mic).
    - The mute button SHOULD trigger the system mute (mic) through the Telephony, or the Consumer interface can be waived.
- **\[Mandatory\]** If the user presses the mute button on the device or OS, the mute state MUST change.
- **\[Mandatory\]** If the device synchronizes the MUTE state with the OS, then the mute state indicator (e.g., LED) on the device MUST change.

#### Capture Path - Output Frequency Response

- **\[Mandatory\]** The device MUST be fully functional using the factory default frequency response and gain settings without any manual adjustment of the capture gain on OS.
- **\[Mandatory\]** The following table specifies the computed average RMS
  dBFS level output under signal level 94 dBSPL.

  | Device type | Output level range versus sine tone frequency |||
  | Device type | 1 kHz | 4 kHz | 7 kHz |
  |---|---|---|---|
  | Bluetooth and USB | \[-15, -5\] dBFS | 1kHz value ±5 dB | 1kHz value ±5 dB |
  | 3.5 mm wired | \[-23, 0\] dBFS | \[-23, 0\] dBFS | \[-23, 0\] dBFS |

**Note:** In Bluetooth and USB devices, the response around the 4 kHz and 7 kHz
tones is given relative to the response at 1 kHz.

## Audio Latency

### MINIMUM REQUIREMENTS

- None

### ADDITIONAL REQUIREMENTS

Along with the **Minimum** requirements, a peripheral MUST meet the following
requirements to achieve certification:

#### Latency

- **\[Mandatory\] Output Latency**: Audio playback MUST begin ≤ 500 ms after a user action that initiates playback.

#### Audio-Video (AV) Sync

- **\[Mandatory\] Accuracy**: The audio playback latency report MUST be accurate to real world latency, i.e., ≤ 50 ms.

## Works With Meet Certification

### MINIMUM REQUIREMENTS

There is an existing
[Google Meet hardware peripheral qualification program](https://support.google.com/meethardware/answer/7657004)
covering part of this spec.

Peripherals qualified by the program are exempted from the following
qualification items:

- **Playback Path - Loudness**
- **Capture Path - Output Frequency Response**

### ADDITIONAL REQUIREMENTS

Along with the **Minimum** requirements, a peripheral MUST meet the following
requirements to achieve certification:

- None

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## Revision history

| Date | Version | Notes |
|---|---|---|
| 2026-09-28 | 2.0 | Use minimum and additional requirements format. |
| 2026-07-09 | 1.4 | Updated specification per Revised Product Specs. |
| 2024-09-06 | 1.3 | ChromeOS Compatible spec derived. Initial Partner Site Publication. |
| 2022-09-14 | 1.2 | Updated to v1.2. |
| 2022-08-19 | 1.1 | Updated to v1.1. |
| 2022-08-18 | 1.0 | Related WWCB specification created. |

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