# Configurations

Source: [https://docs.qualcomm.com/doc/80-41102-1/topic/audio-configurations.html](https://docs.qualcomm.com/doc/80-41102-1/topic/audio-configurations.html)

**Audio Interface Configuration**

By default for an NAD device (e.g., SA525M), audio is configured to route through an I2S
      interface. In the TelAF audio service, there are taf\_audio\_OpenPcmRx and
        taf\_audio\_OpenPcmTx APIs available to use a PCM interface. Before using
      these APIs, some configurations must be made to the device.

1. From the /etc folder on the device, edit the audio\_platform\_info\_extcodec.xml file to add the following lines in the <backend\_names> block:

        <device name="SND_DEVICE_OUT_VOICE_HEADPHONES" backend="auxpcm"/>
        <device name="SND_DEVICE_OUT_ECALL_HEADPHONES" backend="auxpcm"/>
        <device name="SND_DEVICE_IN_HANDSET_MIC" backend="auxpcm"/>
        <device name="SND_DEVICE_IN_VOICE_HEADSET_MIC" backend="auxpcm"/>
        <device name="SND_DEVICE_IN_ECALL_HEADSET_MIC" backend="auxpcm"/>Copy to clipboard
2. From the /etc folder on the device, edit the mixer\_paths\_extcodec\_i2s.xml file to add the following content:

        <path name="voicemmode1-call auxpcm">
            <ctl name="VoiceMMode1_Tx Mixer AUX_PCM_TX_MMode1" value="1" />
            <ctl name="AUX_PCM_RX_Voice Mixer VoiceMMode1" value="1" />
            <ctl name="AUX_PCM_RX_Voice Mixer DTMF" value="1" />
        </path>
        <path name="audio-record auxpcm">
            <ctl name="MultiMedia1 Mixer AUX_PCM_UL_TX" value="1" />
        </path>
        <path name="deep-buffer-playback auxpcm">
            <ctl name="AUX_PCM_RX Audio Mixer MultiMedia1" value="1" />
        </path>Copy to clipboard

Last Published: May 12, 2026

[Previous Topic
Sample audio apps](https://docs.qualcomm.com/bundle/publicresource/80-41102-1/topics/sample_audio_apps.md) [Next Topic
TelAF RPC](https://docs.qualcomm.com/bundle/publicresource/80-41102-1/topics/rpc.md)