[asterisk-users] More DTMF issues

[Brent Davidson]

To add some further details to this thread I set up a "Monitor" command 
that records just the IVR portion of an incoming call.  I left the m 
flag off so I could listen to the incoming audio separate from the 
outgoing recording.  On calls where the DTMF detection works correctly I 
only hear extremely short clips of the DTMF tone in the incoming audio 
sample.  They usually sound like just a click in the audio stream but 
there is a hint of the DTMF tone in the background.  I'm assuming that 
Asterisk and/or my X100P is recognizing the DTMF tones immediately and 
muting them out of the audio path as soon as they are detected.  What 
gets left behind is just the initial sample.

The calls where DTMF detection is not working sound completely 
different.  The tones in those audio streams are very loud and very 
distorted.  It sounds almost like an old Atari 2600 video game instead 
of DTMF tones.  The odd thing is that I can hear a hint of the correct 
tone in the background of the audio.  When the caller is routed to the 
operator extension the voice audio quality is fine.  Also, our outgoing 
greeting is noticeably quieter than the incoming DTMF tones so it 
shouldn't be interfering.  I currently have rxgain set at 0.0 and have 
to set txgain to 4.5 or callers complain that our outgoing audio is too 
quiet.

As much as I would love to say this is a problem with the Caller's PBX I 
just don't see how that's possible.  They never had any problems calling 
us with our old phone system, and it is not limited to any one caller.

Thanks,
Brent Davidson

Brent Davidson wrote:
> Still grasping at straws trying to solve DTMF detection issues with one 
> of my asterisk servers.  This particular server is now running Asterisk 
> 1.4.18.1 and Zaptel 1.4.9.2 in runlevel 3 (console only) with 2 X100P 
> cards.  I have tried adjusting channel gains, turning call progress and 
> relaxdtmf on and off, switching echo cancelers, just about everything 
> that Google turns up and I can't seem to solve the problem. 
>
> If I turn relaxDTMF off then most incoming calls from Cell Phones cannot 
> navigate our menu and I get doubled digits showing up in the log.  With 
> it enabled 99% of calls work correctly, but a few of the calls do not 
> show ANY dtmf digits being passed at all.  I have debug and verbose both 
> set to 20 and have several debugging NoOps set in the dial plan to add 
> some call-flow tracking to the log.  When someone calls in that has 
> problems with DTMF our main greeting plays all the way through and the 
> WaitExten times out and they are sent to our operator extension.  I'm 
> not 100% sure yet if this is relavant, but the majority of the people 
> experiencing this problem are calling in from locations that have their 
> own internal PBX systems.  Is there maybe a way to further relax the 
> DTMF detection?
>
> Thanks,
> Brent Davidson
>
>
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