[asterisk-bugs] [Asterisk 0015024]: DTMF is not working correctly for cell phones.

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=15024 
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Reported By:                alexo
Assigned To:                
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Project:                    Asterisk
Issue ID:                   15024
Category:                   Channels/chan_dahdi
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.4.24 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-05-03 15:12 CDT
Last Modified:              2009-05-05 10:50 CDT
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Summary:                    DTMF is not working correctly for cell phones.
Description: 
We have an issue calling the extension number from cell phones. Sometime is
works, but mostly fails.

The problem is that DTMF tones are coming as doubles or just in wrong
order. I'll attach asterisk console output for cell phones and land one
(yes, land phones works as expected - always).

Any help is really appreciated as most of our customers are mobile.
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Relationships       ID      Summary
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related to          0014815 [patch] DTMF Appears to be broken from ...
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 (0104219) dimas (reporter) - 2009-05-05 10:50
 http://bugs.digium.com/view.php?id=15024#c104219 
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First of all, mp3 is a bad idea. wav files would be better.
Have you played these files yourself? even the naked ear hears that there
is a big problems with the sound (compare what you hear in this file to
what you hear in the phone headset when you press "2").
The DTMF signal is kind of "pulsating". And in any sound editor you will
see that during 400 ms DTMF digit the amplitude drops to zero for at least
10 milliseconds six times! That is enough to consider inter-digit gap.

I'm not sure if the signal you are receiving is really that bad or it is
result of some problems during recording or MP3 encoding. How do you
receive these tones? Do you use some GSM gate or what?

First of all please make sure you understand what "wobbling" I mean - hear
your signals and what an ordinary phone at your desk produces. Next, check
if a person calls your IP phone from mobile and presses digits during a
talk - do you also hear distorted sound or not. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-05-05 10:50 dimas          Note Added: 0104219                          
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