Asterisk 11 T38 invite


I have a Asterisk Server with libss7. ( Asterisk 11.5.0)

We are using this server to terminate calls to Telco.

So calls are coming to asterisk from sip and we are sending calls to Telco with Dahdi. (It is a one way interconnection only from asterisk to telco ,not from telco to asterisk)

We are experiencing some difficulties with T38 faxing.

I set t38pt_udptl=no in sip.conf . So as far as i understood if a call to sip sends T38 invite then asterisk should send SIP 488 Not acceptable here and the sip side will either fallback to onether codec or disconnect.

In my case although i set t38pt_udptl=no in peer configuration asteisk is sending SIP 200 OK with sdp G711 to the invite of T38.

I also tried to set t38pt_udptl = yes,redundancy,maxdatagram=400 and setvar=FAXOPT(gateway)=yes,20 in sip.conf but still i couldn’t manage to receive fax

I will be glad if someone can advice me how to solve this issue

Best Regards