[asterisk-users] DTMF transmitting letter A

Eric Wieling EWieling at nyigc.com
Tue Jun 17 10:33:35 CDT 2014

A is a valid DTMF "digit", chances are your PBX is detecting the digit wrong.   If you have relaxdtmf enabled, disable it.   If that doesn't help, play with the audio gains.  Too loud or too soft can cause DTMF issues.

-----Original Message-----
From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Markus
Sent: Tuesday, June 17, 2014 11:30 AM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: [asterisk-users] DTMF transmitting letter A

Dear list,

maybe not really an Asterisk question, but... all my users dial in via 
PSTN (via SIP DIDs) and enter a target number via DTMF through my 
Asterisk 1.4. Out of about 150,000 calls per month I see on average 
about 1 call per month where an arbitrary caller enters the letter 'A' 
via DTMF. These callers use their mobile phones to dial in. I just 
reread the Wikipedia article on DTMF but I don't understand how someone 
can send an 'A'. Any clue?

Thank you!

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