[SIP Beyond VoIP] sip-session not detecting or debugging DTMF with Payload Types

Jason Ostrom jostrom at gmail.com
Sun Feb 2 23:13:47 CET 2014

Trying to get a sample client app able to detect DTMF and print to stdout.   RFC2833 DTMF packets are received through DTMF passthrough, but no detection or printing to stdout.

I have checked out latest sip simple SDK and sipclients source from darcs repo.  

Have Tried:

Using sample 'sip-session' application, and tried PJSIP logging ('--trace-pjsip') and --trace-notifications:  

Verified with pcap / wireshark that host running sip-session is receiving DTMF and it is RFC 2833.  Problem appears to be:

rtpmap in SIP INVITE for telephone-event is value of payload type '96'.  However, when RTP DMTF packets are received by app, the Payload Type is 'DynamicRTP-Type-101 (101)'.

I think according to Saúl this is the problem, that the actual payload type in RTP is not 96 and SIP Simple expects 96.  However, shouldn't this still be handled by latest source code?  Is there anything else that can be done debugging script to help solve this problem?

Has anyone been able to configure Asterisk to correctly send DTMF matched with static payload types such as 96, so that SIP Simple SDK sample client can easily detect and print DTMF digits dialed?  Anyone resolved this problem through another tip or hint?

Thank you in advance.

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