I’m still trying to get a working t.38 configuration w/ pjsip.
I’m now able to send t.38 faxes to my own extension:
hylafax -> t38modem -> extension -> extension -> t38modem -> hylafax.
The fax is sent by t38modem. The receiving part of t38modem accepts the call, sends ReInvite for t.38 and things are working as expected.
Now, let’s do the nearly same thing, but use an ISP:
hylafax -> t38modem -> extension -> trunk -> ISP ->
trunk -> extension -> t39modem(2) -> hylafax
Same procedure: the receiving t38modem(2) sends ReInvite for t.38 – but this time, the extension / asterisk just ignores it. After the 5. retry to switch to T.38, asterisk tells:
res_pjsip_t38.c:207 t38_automatic_reject: Automatically rejecting T.38
request on channel ‘PJSIP/91-00000007’
=> Why does asterisk reject the switch / ReInvite to T.38 this time? It never even tried to send it to the ISP!
Thanks for any hint!