On 05/30/2018 01:13 PM, John R. Levine wrote:
Can anyone recommend software that sends faxes over SIP?
No. Just NO. The problem is that all the modulation methods that FAX transmission use requires time stability in the analog channel, and there is no way that SIP is going to be that stable. How do I know this? A number of years ago, a cable system maker asked me to consult on why V.29 fax wouldn't work over their voice-over-coax solution. I used a 23-tone test on the analog channel for 24 hours, and found the phase jitter was off the charts -- no way that fax machines could send faxes over the analog channel. (Traced it to the timing chain oscillating across the system.) Have you considered paying the $0.50 per page to have the local copy shop send the once-a-month faxes? The other answers have far superior suggestions sending fax over TCP/IP.