[asterisk-users] T.38 SIP Issues

[Andreas van dem Helge]

Is there any trick to getting T.38 fax to work with SIP? I had it
working and one day with no changes *poof* it stopped working and
hasn't worked for months. The only common factor is Asterisk 1.4.x
(always try to use the latest version) and NAT.

I've tried:

-Linksys ATA
-Grandstream ATA
-Audicodes ATA

All do the same thing. Call connects, hear the first 2sec of fax tone
and then just silence, but the call usually stays open.

I've tried two T.38-capable providers.

I've tried two different routers:
-Linksys WRT54GS running DD-WRT (Linux)
-Dell Optiplex 170L running PFSense (BSD)

Different Linux distros on the servers:
-SuSE 64bit
-RHEL 32bit
-SuSE 32bit

Is there any magic to get this to work? As far as I can tell the only
possible config option is "t38pt_udptl = yes" which I have set under
[general] & the peer.