DTMF in 183 Session in Progress


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DTMF in 183 Session in Progress

  • Hi,

    When somebody makes a call to HMP (linux relase ) after i send 183 Session in Progress is it possible to get DTMF  before 200 OK ? 

    After i answer the call with 200 OK it works ,but i would like to be able to detect DTMF before i send 200 OK because after i answer with 200 OK billing takes place. 

    I would appreciate any advice on this subject. 

    Thanks  in advance 

  • I believe only in in-band dtmf sent within the RTP stream itself can be detected at the voice channel level. As usage of RFC2833 will only be set for the mediastream once the call is fully establish after the ACK is sent back to connect the call.


  • Hi

    I read that it is possible to have 2 way rtp before 200 OK.

    Does HMP support this ?


    4.2. Forward Early Media ........................................5