[Linphone-developers] oRTP question

[Henning Christiansen]

Hi,
I have got a question abour oRTP.

I establish a SIP connection qnd transfer RTP packets between both ends.

RTP transfer is started like this:

    rtpSession = rtp_session_new(RTP_SESSION_SENDRECV);
    rtp_session_set_scheduling_mode (rtpSession, 1);
    rtp_session_set_blocking_mode (rtpSession, 1);
    rtp_session_set_profile(rtpSession, &av_profile);
    rtp_session_set_jitter_compensation(rtpSession,
                          pSipua->sipServer[usedSIPServer].jitterCompensation);
    rtp_session_set_local_addr(rtpSession, pSipua->localIP,
                               pCsd->localRTPPort);
    rtp_session_set_remote_addr(rtpSession,
                               pCsd->remoteSDPAudioIP,
                               pCsd->remoteRTPPort);
    iRetVal = rtp_session_set_payload_type(rtpSession, pCsd->rtpPayload);

During this connection I would like to transfer DTMF packets according to 
RFC 2833. This is done with a call to procedure

    rtp_session_send_dtmf(...).

This procedure call fails (returns error code), and there is an indication

  "telephonyevents.c:74- assertionsession->telephone_events_pt!=-1failed

I see from the documentation that RFC2833 transfers are not working "if the 
session cannot support telephony events".

My questions:

1. How can I configre the session to support tis type of events?
2. Can I do this one when starting the communication after "rtp_session_new"?
3. Or do I have to toggle between both modes, i.e. activate/deactivate the 
support with every DTMF digit to be sent?

Thank you very much for your support!