I’m having ongoing difficulties sending and receiving faxes reliably. I have medical practices regularly faxing us and having calls drop mid-fax for no obvious reason I can discern. “fax show stats” gives me the following (presumably this is just stats since the last restart):
FAX Statistics: --------------- Current Sessions : 0 Reserved Sessions : 0 Transmit Attempts : 1 Receive Attempts : 11 Completed FAXes : 12 Failed FAXes : 9 Spandsp G.711 Success : 0 Switched to T.38 : 1 Call Dropped : 0 No FAX : 0 Negotiation Failed : 0 Train Failure : 0 Retries Exceeded : 0 Protocol Error : 0 TX Protocol Error : 0 RX Protocol Error : 0 File Error : 0 Memory Error : 0 Unknown Error : 0 Spandsp T.38 Success : 3 Call Dropped : 3 No FAX : 0 Negotiation Failed : 0 Train Failure : 0 Retries Exceeded : 6 Protocol Error : 0 TX Protocol Error : 0 RX Protocol Error : 0 File Error : 0 Memory Error : 0 Unknown Error : 0
I’ve discovered one of our phone companies provides a fax-back test service. You send it a fax and a few seconds later it sends back information about your fax.
Sending and receiving to this service has never dropped out. The results I get back tell me:
Overall performance: Poor Transmission level: Poor Training signal quality: Excellent Transmission speed: Excellent Facsimile image transmission: Poor
The recommendation says:
Your facsimile transmit level is 5.7 dB TOO HIGH. Please contact your supplier
Other information it gives is that there was 1 “unknown G3 code line”, 4 “empty image lines, excl RTC” and 699 “unfilled scan lines”. All of these it says should be 0.
Is any of this relevant when faxing through Asterisk? Does it tell me anything useful to help me understand what’s failing? Any guidance greatly appreciated.