[asterisk-users] T.38 with Audiocodes gateway [SOLVED]

[Olivier]

2016-05-03 16:43 GMT+02:00 Matt Fredrickson <creslin at digium.com>:

> On Fri, Apr 29, 2016 at 1:34 AM, Olivier <oza.4h07 at gmail.com> wrote:
> > Hello,
> >
> > I'm helping a colleague (*) which has the following setup:
> >
> > ITSP --- <T.38 capable PJSIP trunk> --- Asterisk 13 ---  <PJSIP>--
> > Audiocodes MP-112 ---  <FXO/FXS> --- Fax machine
> >
> > My issue is the following :
> > Audiocodes gateway reject INVITEs with 488 Not Acceptable Here
> >
> > It seems this gateway requires t38 settings to be present in SDP body in
> the
> > very first INVITE.
> >
> > My questions are the following:
> >
> > 1. I expected T.38 to exclusively work with reINVITE where calls are
> > established as normal voice calls (PCMA/PCMU in SDP, for instance) and
> then
> > upgraded to T.38 (when CNG is detected, for instance).
> > Have you ever heard of T.38 sessions being established right from the
> start
> > (ie with T.38 settings in the first INVITE) ?
>
> No.  It would seem to be extremely broken if it denies a call based on
> a lack of T.38 sdp parameters on the initial INVITE.
>

OK

>
> > 2. Is it possible to configure Asterisk to pass T.38 settings in SDP in
> the
> > first INVITE it sends ?
> >
> > 3. Any suggestion with Audiocodes gateway ?
>
> Look for T.38 settings maybe?  See if there is something keeping you
> from sending an initial invite with non-T.38 SDP....?
>

Yes, I think issue must come from incorrect Audiocodes settings.
Requiring T.38 settings within first INVITE seems very unusual.

Thank you very much for replying

>
> --
> Matthew Fredrickson
> Digium, Inc. | Engineering Manager
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
>
> --
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