Hi,

On Thu, 2007-05-24 at 09:17 -0700, Armando Rodriguez wrote:
> Dear Matteo Branceleoni and Daniel Orlandi,
> 
> Last year I have figured out a bug regarding the
> misdetection of DTMF digits on vGSM channel. This
> issue was later fixed and an option of "relaxdtmf" was
> added to the vgsm.conf file.
> At some point this fixed the problem. But there are
> still operators that vGSM is having trouble with
> detecting those DTMFs
> And because of this I would kindly ask your help, to
> point me to the piece of code that is responsible for
> DTMF detection.
We simply use * DSP, nothing more, to detect DTMFs.

The problem with DTMF over GSM is that dtmf are sent
inband from telco to GSM channel (outofband viceversa),
so the GSM modulation can corrupt the DTMF causing
erroneos detections.

> Could you kindly advise me of which settings I can
> manipulate to get the preferable results for me.

Playing a bit with GSM modulation, seems that DTMF
are recon pretty well if the modulation used
is gsm full rate. With latest vstuff (see http://open.voismart.it)
is possible to *try* to force the codec used between
gsm module and telco.
If you set it to gsm-fr should work.

Unfortunately here in .it we don't have
gsm-hr (half rate) or amr that seems causing problems.
So we cannot test it :(
So test it and report to us.

Greetings,
Matteo

-- 
Matteo Brancaleoni
R&D Director
Tel  :+39.02.70633354
Voip :sip:[EMAIL PROTECTED]

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