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Strange DTMF received on a incoming call

eigbar
eigbar asked
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Last Modified: 2013-12-21
We have a Asterisk 1.4.21.2 box conected to several VoiP trunks and E1 links (through Mediant 1000 gateways), and the calls are sent to SIP peers. Sometimes, during incoming calls, our users are able to hear some beeps similar to DTMF digits. See examples bellow (they are portuguese conversation, but you can hear the sounds).

http://www.katizak.locaweb.com.br/asterisk/beep.mp3
http://www.katizak.locaweb.com.br/asterisk/beep2.mp3
http://www.katizak.locaweb.com.br/asterisk/beep3.mp3
http://www.katizak.locaweb.com.br/asterisk/beep4.mp3

On the other side of the conversation, we are pretty sure they are not pressing any button in their phones.

Do you guys have any guess about where these sounds are coming from? Is there any configuration that can prevent the SIP peers from receiving DTMF digits, while they still can send DTMF outside?

Thanks for any help you may provide!
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feptiasChief Dude
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Hi,

Actually we do not use Zap/E1 boards. We have E1 links coming into Mediant 1000 gateways, whose sends all calls to a Asterisk 1.4.19 box, via SIP signaling. This box acts like a "SIP router", sending the call to the final Asterisk 1.4.21.2 that should handle the call, again via SIP signaling.

Also, we have SIP lines that are registered straight in the Asterisk box that handles the incoming calls, and in this case the issue happens as well.

Our Asterisk boxes have the sip parameter "relaxdtmf" set to no.

Any other idea?
feptiasChief Dude
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We are using dtmfmode=rfc2833 for all sip users. What setting do you recommend? Please keep in mind that DTMF tones are necessary when our users call a IVR, for example...
feptiasChief Dude
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