sending & receiving DTMF on gateways

Unanswered Question
Sep 23rd, 2010

Hi,

I see that I receive the DMTF tones but are these DTMFs also send to the calling party ? how can I be sure ?

thanks

*Sep 23 05:31:01.720:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x191F timestamp 0x3520FEB3
*Sep 23 05:31:01.720:  <<<Rcv> Pt:99     Evt:7       Pkt:08 00 00
*Sep 23 05:31:01.720:          s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x191F timestamp 0x3520FEB3
*Sep 23 05:31:01.720:          Pt:99     Evt:7       Pkt:08 00 00  <Snd>>>
*Sep 23 05:31:01.720:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x1921 timestamp 0x3520FEB3
*Sep 23 05:31:01.720:  <<<Rcv> Pt:99     Evt:7       Pkt:08 00 00
*Sep 23 05:31:01.720:          s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x1921 timestamp 0x3520FEB3
*Sep 23 05:31:01.720:          Pt:99     Evt:7       Pkt:08 00 00  <Snd>>>
*Sep 23 05:31:01.720:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x1920 timestamp 0x3520FEB3
*Sep 23 05:31:01.720:  <<<Rcv> Pt:99     Evt:7       Pkt:08 00 00
*Sep 23 05:31:01.720:          s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x1920 timestamp 0x3520FEB3
*Sep 23 05:31:01.720:          Pt:99     Evt:7       Pkt:08 00 00  <Snd>>>
*Sep 23 05:31:01.764:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x1922 timestamp 0x3520FEB3
*Sep 23 05:31:01.764:  <<<Rcv> Pt:99     Evt:7       Pkt:08 01 90
*Sep 23 05:31:01.764:          s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x1922 timestamp 0x3520FEB3
*Sep 23 05:31:01.764:          Pt:99     Evt:7       Pkt:08 01 90  <Snd>>>
*Sep 23 05:31:01.816:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x1923 timestamp 0x3520FEB3
*Sep 23 05:31:01.816:  <<<Rcv> Pt:99     Evt:7       Pkt:08 03 20
*Sep 23 05:31:01.816:          s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x1923 timestamp 0x3520FEB3
*Sep 23 05:31:01.816:          Pt:99     Evt:7       Pkt:08 03 20  <Snd>>>
*Sep 23 05:31:01.868:          s=VoIP d=DSP payload 0x63 ssrc 0x41900A2 sequence 0x1924 timestamp 0x3520FEB3
*Sep 23 05:31:01.868:  <<<Rcv> Pt:99     Evt:7       Pkt:08 04 B0

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
Felipe Garrido Thu, 09/23/2010 - 06:45

   s=DSP d=VoIP payload 0x63 ssrc 0x41900A2 sequence 0x191F timestamp 0x3520FEB3
*Sep 23 05:31:01.720:          Pt:99     Evt:7       Pkt:08 00 00  >>

The above debug line indicates that we are sending the RTP event on the outgoing leg. To verify, collect a packet capture off of the terminating device. It should show the RTP events. Only thing to watch out for is the non-standard payload type. Looks like whoever is sending the events is using 99. The default with Cisco devices is 101.

The above is assuming that we're looking at a CUBE set to do SIP on both call legs.

-Felipe

blackswans Mon, 10/25/2010 - 22:59

I know that we can change the payload type on dial peers with the command

rtp payload-type nte 99

IS there a way to change the payload type on call manager ?

Felipe Garrido Tue, 10/26/2010 - 06:24

The payload for rfc2833 events can be changed when invoking an MTP on the SIP trunk in CUCM.  The field is Default MTP Telephony Event Payload Type under the SIP Profile Configuration Page.

The payload cannot be changed for SCCP endpoints that support rfc2833.This limitation is documented in CSCtb57450.

-Felipe

Actions

This Discussion