SIP fax sending software?

James Cloos cloos at
Sat Jun 2 18:57:17 UTC 2018

>>>>> "JL" == John R Levine <johnl at> writes:

JL> Can anyone recommend software that sends faxes over SIP?

I've had good luck using asterisk's res_fax_spandsp, sending to twilio
(which supports t38).  Freeswitch's t38 support also is said to work well.

Hylafax, iaxmodem and asterisk has worked well for mulaw faxing, provided
a low-jitter path to the pstn provider, but lately I've been using the
above path.

Of course that is probably only one fax every few months.

James Cloos <cloos at>         OpenPGP: 0x997A9F17ED7DAEA6

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