Tone detector

This helper module provides inband detection of DTMF, DNIS, Fax and Continuity tones. The audio signal must be perfect quality (no codecs in the data path) which normally means that only uncompressed slin and G.711 (alaw or mulaw) will work.

The module creates and attaches data consumers by handling the chan.attach and chan.record messages.

When a DTMF is detected the module masquerades a chan.dtmf as the channel to which it is attached. On detection of a continuity tone a DTMF with the text O is masqueraded.

When a DNIS is detected the module masquerades a chan.notify as the channel to which it is attached.

When a Fax CNG (or, as an option, CED) tone is detected the module can either masquerade a call.fax message or directly divert the call to another target by masquerading a call.execute to a specified target.

Tone detector resource format

The general format is tone/[channel/]mode where:

channel

channel side to detect, can be left, right, mixed or mono (default)

mode

what to detect, can be * or a comma separated list of dtmf, fax, rfax, cotv, cots and callsetup

• dmtf - detect DTMFs
• fax - detect Fax CNG
• rfax - detect Fax CED (reverse direction, exclusive with fax)
• cotv - detect Continuity Verify
• cots - detect Continuity Send (exclusive with cotv)
• callsetup - detect DNIS during call setup, used in E&M signaling

A single * is equivalent to dtmf,fax

Parameters for chan.attach

consumer

specify a tone detect resource if the detector must attach as the consumer

sniffer

specify a tone detect resource if the detector must attach as a sniffer

Parameters for chan.record

call

must specify a tone detect resource

id

optional, apparent ID of the channel if attaching to a DataEndpoint

Common parameters

notify

optional target for chan.notify when a DNIS is detected

fax_divert

optional target for automatic divert of a Fax

caller

caller party number to masquerade when diverting a Fax

called

called party number to masquerade when diverting a Fax

Message examples

chan.attach

sniffer=tone/*
fax_divert=fax/receive/test.tiff
caller=12345
called=67890

chan.record

call=tone/left/dtmf,fax,cotv
notify=dialer/115

See also

• chan.attach
• chan.record