T.38 Incoming Fax Problem

Home » Asterisk Users » T.38 Incoming Fax Problem
Asterisk Users No Comments


I’ve installed the free (one user) Fax for Asterisk (FFA) license.
Outgoing faxes, using T.38, to the PSTN work quite well. However,
incoming faxes, do not seem to detect tones and certainly do not switch
to T.38. The call drops as soon as the fax answers.

Since I am using FreePBX (, I am trying to modify the adjunct
files to make this work. That makes it a little more confusing for me to

In the sip_general_custom.conf file, I have added:


I am sure something else is missing. The IP PBX simply does not detect
the tones nor tell the switch to implement T.38. If you have some ideas,
please let me know. I sure appreciate the help.

AsteriskNOW 1.7.1