[asterisk-app-dev] absorbDTMF option only working on one channel

[Joshua C. Colp]

On Wed, Dec 18, 2019 at 8:56 AM Richard Frith-Macdonald <
richard.frith-macdonald at engagehub.com> wrote:

>
>
> > On 18 Dec 2019, at 12:28, Joshua C. Colp <jcolp at sangoma.com> wrote:
> >
> >
> > For the non-mobile leg is it configured with dtmf_mode=rfc4733?
>
> There's no specific dtmf_mode configured for it, which the documentation
> says means rfc4733 (the default).
>
> > If so then it looks as though from the perspective of Asterisk it is not
> actually forwarding DTMF through, at least DTMF it has been told about. If
> the DTMF is also coming in over the audio stream itself, then that would be
> forwarded on as-is since it is the responsibility of the remote party to
> suppress that audio and not Asterisk.
>
> Shouldn't I be seeing that in the log as RTP packets?  I don't see any
> audio packets interleaved with the DTMF ones.
>

It depends where exactly it's inserted into the audio stream. It's all just
theories right now and suggestions on how to narrow things down.


> > A test would be sending the mobile leg to Record() and seeing if the
> DTMF is recorded. Record() doesn't record DTMF that Asterisk knows about,
> but merely records the audio stream as received. If it's played back and
> there is DTMF then it's not being suppressed as expected by the remote side.
>
> I'll try that later.
>
> If the remote side (mobile phone / network operator / SIP provider) is
> sending DTMF both in rfc4733 form and in the audio dat itself, is there
> anything asterisk can do to remedy that (eg apply a notch filter to the
> audio before passing it on over the brdge)?
>

Nothing springs to mind. We really depend on the remote endpoint to remove
it.

-- 
Joshua C. Colp
Asterisk Technical Lead
Sangoma Technologies
Check us out at www.sangoma.com and www.asterisk.org
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