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Faxing Through PBXNSIP

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I'm trying to fax through pbxnsip and i'm having lots of problems. I've got my ATA as an extension and my fax server plugged into the ATA. Whenever I dial my fax number, i get the fax tone for about 1 second and it is supressed to silence. If i try to send faxes, they fail. I can't determine if my ATA is supressing the tone or if pbxnsip is doing it. I've checked that "silence supression" is switched off in my ATA.


Can someone please advise me if they've had problems with their fax tone being supressed?

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That sounds like the FAX tries to re-negotiate T.38 and that fails for some reason. Make sure that both sides support this wonderful protocol. You should be able to see the T.38 negotiation by looking at the SIP packets of the devices.


Unfortunately, T.38 is not a real SIP success story yet. The IETF made it freaking complicated and there are a lot of more or less buggy devices out there.

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