We run a Sangoma card that, until recently, had the TDMV_HW_FAX_DETECT hardware fax detection enabled. I thought that this option was designed to switch off echo cancellation upon the detection of a fax tone, but it turns out that it actually sends and event to DAHDi/Asterisk to switch to the “fax” extension, even though we receive all of our faxes on a dedicated DID. We also had “faxdetect=incoming” enabled in our chan_dahdi.conf file.
The upshot was that we were getting a lot of random disconnects because of false fax detections that redirected non-fax calls to the fax extension, which resulted in a lot of these messages showing up in the logs:
NOTICE chan_dahdi.c: Fax detected, but no fax extension
Which brings me to my question: Is there somewhere, or shouldn’t there be somewhere, that I can specify what to do with a fax call if there is no fax extension in that context? Basically, if I had been able to configure it such that all fax calls were answered by FFA, callers would have mentioned “I had a fax machine squeal in my ear!” instead of “I don’t know, it just hung up on me!”
I don’t want to specify a fax destination for all of my inbound routes, as there shouldn’t be any fax calls coming in on those DIDs. HOWEVER, I would like to be able to specify system-wide:
“If, for some reason, you get shunted to the fax extension, go here”
At least that way I can make sure that customers won’t just get hung up on, they will get directed to where I want them.
Just a thought. I never think it’s a good idea to just hang up on someone.