Module or Location of file for fax_detect

Centos 7
Asterisk 13

Amateur programmer here but I want to try to attempt to look through the ‘C’ codes. Could someone direct in the right direction. Where is the module for file of ‘fax_detect’ which the bool is usually located in pjsip.conf.

I want to see the frequency that asterisk is listening on. From my understanding fax incoming generates a freq tone on 1100 hz but when trying to detect fax on outgoing, it generate a tone of 2100 hz correct me if im wrong so I was wondering if I can edit the AMD function and add additional parameters to the function to listen on outgoing/incoming fax tone within dialplan.

Reference: Tone

These frequencies are defined by ITU standards, and it would probably be better to refer to those directly than to reverse engineer Asterisk.

A secondary source would seem to be

Incidentally 2100Hz is used by many modems, not just those used for fax, and it is really there to signal to, particularly analogue, networks that a full duplex path, with no echo suppression, is needed.

1 Like