[SIP Beyond VoIP] Debugging DTMF for conference bridge app

Saúl Ibarra Corretgé saul at ag-projects.com
Mon Dec 23 09:14:56 CET 2013


On Dec 21, 2013, at 7:09 PM, Jason Ostrom <jpo at pobox.com> wrote:

> I have done the following in order to have SIP Simple print out the DTMF, and it is still not working.
> 1.  Ported code from sip-session sample sipclients for DTMF receiving into other python script.  The code is listening for notification from the audio stream just as sip-session does.

How did you add the observer?

> 2.  Verified that the DTMF is being received as RFC 2833 and it is broadcasted by Asterisk.  Ran a wireshark trace and all digits are being received on host running sip simple SDK apps.
> Problem is SIP Simple code is not able to detect DTMF, or at least my implementation.
> Question:  How do I get the "sip-session" sample application to receive DTMF and print out each DTMF digit to stdout?  Does it do this by default?  How do I debug / print each RTP packet, because DTMF in RTP Payload is not detected?  I am trying to troubleshoot it, if I can just get sip-session to print each DTMF digit that is broadcasted by another conference user, then I can get the 'sip-session' DTMF receiving code working in the other python script.  Both scripts are successfully dialing into conference.  Other conference user inputs DTMF, and I can see Asterisk broadcasting, but nothing on receiving scripts.  Please let me know if any ideas.

You can enable notifications trace (see sip-session -h) and all notifications will be either dumped to a file or printed to stdout. You should see if DTMF is detected notifications getting fired. If it isn't detected, then you'd need to dig deeper and enable the PJSIP logs.


Saúl Ibarra Corretgé
AG Projects

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