[asterisk-users] What t38pt_udptl is ? Explain T.38 in 1.4

[Benny Amorsen]

Olivier <oza-4h07 at myamail.com> writes:

> So I must be misunderstanding what t38pt_udptl=no means.
> Maybe it simply means "if t38pt_udptl=yes, then use this type of T.38,
> else use another type of T.38" and setting t38pt_udptl=no is not enough to
> prevent an endpoint to receive T.38 offers ...

There are two facts you need to bear in mind when doing T.38 in 1.4
1) Asterisk 1.4 won't "transcode" between T.38 and ulaw/Alaw
2) The two call legs negotiate codecs independently

So what happens is that a call comes in from a T.38-capable device,
and Asterisk negotiates T.38. The Dial ends up going to a
non-T.38-capable device, but Asterisk won't transcode, so it sends out
T.38 anyway.

This problem makes T.38-support in Asterisk 1.4 fairly useless IMHO,
but maybe you can find a workaround. Luckily it works brilliantly in
1.6.


/Benny