One-Touch Call Recording

Let users start and stop call recording by pressing a DTMF key during an active call. This uses the automixmon feature map entry, which toggles MixMonitor on and off.

Features Configuration (features.conf)

[featuremap]
automixmon => *3      ; Press *3 to toggle recording on/off

[applicationmap]
; Optional: custom recording feature with specific filename
custom_record => *4,self,MixMonitor,${STRFTIME(${EPOCH},%Y%m%d-%H%M%S)}-${CALLERID(num)}.wav,b

Dialplan: Enabling Recording Features

[internal]
; Using built-in automixmon (X option enables it for callee, x for caller)
exten => _1XXX,1,NoOp(Call with one-touch recording enabled)
 same => n,Dial(PJSIP/${EXTEN},30,xX)
 same => n,Hangup()

; Using custom recording via DYNAMIC_FEATURES
exten => _2XXX,1,NoOp(Call with custom recording feature)
 same => n,Set(__DYNAMIC_FEATURES=custom_record)
 same => n,Dial(PJSIP/${EXTEN},30,Tt)
 same => n,Hangup()

; Always-on recording (no DTMF toggle needed)
exten => _3XXX,1,NoOp(Auto-recorded call)
 same => n,MixMonitor(${UNIQUEID}.wav,ab)
 same => n,Dial(PJSIP/${EXTEN},30)
 same => n,StopMixMonitor()
 same => n,Hangup()

How it works

1. automixmon: A built-in feature map entry that toggles MixMonitor on the channel. The first press starts recording, the second press stops it. Audio from both sides is mixed into a single file.
2. Dial() options x and X: Lowercase x allows the caller to trigger automixmon. Uppercase X allows the callee. Use both (xX) to let either party record.
3. MixMonitor vs Monitor: MixMonitor records both sides into a single file. The older Monitor application records each direction into separate files (-in.wav and -out.wav). MixMonitor is preferred.
4. Recording location: By default, recordings are saved to /var/spool/asterisk/monitor/. The filename defaults to the channel name. Use MixMonitor(filename.wav) to set a custom name.
5. MixMonitor options: a appends to an existing file, b bridges audio from both channels immediately. Without b, recording starts only when the call is answered.

Tips

• Name recordings meaningfully: MixMonitor(${STRFTIME(${EPOCH},%Y%m%d-%H%M%S)}-${CALLERID(num)}-${EXTEN}.wav,b) produces filenames like 20260214-143052-5551234-1001.wav.
• Set recordingfailsound = beeperr in [general] of features.conf to play an audible warning if recording fails to start.
• Check active recordings: mixmonitor list <channel> on the CLI.
• For compliance recording (all calls), use MixMonitor() in the dialplan before Dial() instead of one-touch. One-touch is for on-demand recording.
• Disk space: 8kHz ulaw WAV uses about 480 KB per minute. Set up a cron job to archive or purge old recordings.
• Recording requires func_periodic_hook.so and app_mixmonitor.so modules to be loaded.