Audio Config

Controls alert tones, volume, playback from PCM files, and microphone recording. All audio is 16‑bit PCM at 8 kHz.

Key path: devcfg.audioout, devcfg.audioin

{
  "devcfg": {
    "audioout": {
      "alert": "id",
      "durMS": 1000,
      "vol": 100,
      "ref": "id"
    },
    "audioin": {
      "ref": "id",
      "durS": 10,
      "vad": false
    }
  }
}

Important To play a sound immediately, send an action — do not use devcfg. See Beep action. Setting alert and ref here only changes the default alert tone and playback file used the next time an alert fires; it does not play anything itself.

Audio out

alert

Audio code or ID of the tone/beep to play when an alert is active.

Configuration variables

• Type: string
• Default: none

Code	Type	Description
AT1	Tone	1 kHz continuous
AT2	Tone	2 kHz continuous
AT5	Tone	500 Hz continuous
ABS	Beep	Slow beeps
ABF	Beep	Fast beeps
ABE	Beep	Extremely fast beeps

{ "devcfg": { "audioout": { "alert": "AT2" } } }

durMS

Maximum duration in milliseconds for an alert tone or file playback. The actual sound may stop earlier if the file is shorter.

Configuration variables

• Type: integer
• Default: 1000

{ "devcfg": { "audioout": { "durMS": 2000 } } }

vol

Volume level as a percentage of the nominal gain. 0 = silent, 100 = nominal, 200 = 2× gain.

Configuration variables

• Type: integer (0‑200)
• Default: 100

{ "devcfg": { "audioout": { "vol": 150 } } }

ref

File ID of a raw PCM file to play. The device looks for /audio/<id>.pcm or /audio_rec/<id>.pcm.
The file must be 16‑bit, 8 kHz mono.

Configuration variables

• Type: string
• Default: none

{ "devcfg": { "audioout": { "ref": "my_tune" } } }

song (piezo tunes) is only available on piezo hardware; not implemented on speaker‑based devices.

Audio in

ref

File ID where the recording will be stored. The file is written to /audio_rec/<id>.pcm.

Configuration variables

• Type: string
• Default: none

{ "devcfg": { "audioin": { "ref": "rec1" } } }

durS

Maximum recording time in seconds.

Configuration variables

• Type: integer
• Default: 10

{ "devcfg": { "audioin": { "durS": 30 } } }

vad

If true, the voice activity detector is enabled. Recording only starts when voice is detected, but the total timeout (durS) still applies.

Configuration variables

• Type: boolean
• Default: false

{ "devcfg": { "audioin": { "vad": true } } }

Related

• Audio Results (Uplink) — playback and recording result codes
• Alert Config — alert sound and vibration settings
• App Actions — beep and vibr actions