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-boun...@lists.digium.com [mailto:asterisk-users-boun...@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! Markus -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users