DTMF Debugging

To debug DTMF events from a connected SIP device (trunk/phone) using SIP-KPML (or Notify) use

debug ccsip messages

Apr 18 19:46:38.060: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg:
NOTIFY sip:+441245001999@ SIP/2.0
Via: SIP/2.0/UDP;branch=z9hG4bK62e20538
To: <sip:+441245001999@>;tag=266210C-DC3
From: “Doggie” <sip:5001004@>;tag=aca0166f217300451267f6cd-00e42f52
Call-ID: aca0166f-21730029-00685cda-411f1c34@
Date: Tue, 18 Apr 2017 19:46:29 GMT
CSeq: 422 NOTIFY
Event: kpml
Subscription-State: active; expires=6000
Max-Forwards: 70
Contact: <sip:A5AC-2125@;transport=udp>
Content-Length: 201
Content-Type: application/kpml-response+xml
Content-Disposition: session;handling=required
<?xml version=”1.0″ encoding=”UTF-8″?>
<kpml-response xmlns=”urn:ietf:params:xml:ns:kpml-response” version=”1.0″ code=”200″ text=”OK” suppressed=”false” forced_flush=”false” digits=”2″ tag=”dtmf”/>


Apr 18 19:46:38.064: //0/000000000000/SIP/Msg/ccsipDisplayMsg:
SIP/2.0 200 OK
Via: SIP/2.0/UDP;branch=z9hG4bK62e20538
From: “Doggie” <sip:5001004@>;tag=aca0166f217300451267f6cd-00e42f52
To: <sip:+441245001999@>;tag=266210C-DC3
Date: Tue, 18 Apr 2017 19:46:38 GMT
Call-ID: aca0166f-21730029-00685cda-411f1c34@
CSeq: 422 NOTIFY
Content-Length: 0

To debug on IOS GW for DTMF outgoing on to PSTN (e.g. PRI) use

debug voip vtsp session

Apr 18 19:43:42.503: //6046/C2FF91A397E9/VTSP:(0/2/0:15):0:1:1/vtsp_call_digit_begin:
Begin Digit=2

Apr 18 19:43:42.503: //6046/C2FF91A397E9/VTSP:(0/2/0:15):0:1:1/vtsp_call_digit_end:
End Digit=2, Duration=250

In CUCM RTMT look for “tone” and “MediaTerminationPointControl”, example below shows the CUCM received DTMF which has been received via SIP-KPML from a SIP Trunk which is destined for an MCU conference. The MCU supports RFC2833 only. CUCM uses the outbound call leg MRGL which is the MCU as the call was made into the MCU. The MTP from this MRGL is used to convert from KPML to RFC2833 and is shown in “MediaTerminationPointControl” RTMT debug.

00925348.001 |20:30:23.093 |AppInfo  |SIPCdpc(35) – star_CcUserInfoReq: Outbound DTMF method selected is 2. Digit=6 and isMTPPassingThru2833=0

00925348.002 |20:30:23.093 |AppInfo  |SIPCdpc(35) – sendDtmfVia2833: sending sipOutgoingDTMFTone Tone 6 for digit 6.

00925349.000 |20:30:23.093 |SdlSig   |SIPOutgoingDTMFTone                    |sessionEstablished             |SIPInterface(1,100,77,23)        |SIPCdpc(1,100,83,35)             |1,100,10,1.4702^^*            |[R:N-H:0,N:0,L:0,V:0,Z:0,D:0]  tone=6 isMTPPassingThru2833=F

00925350.000 |20:30:23.093 |SdlSig   |MXOutgoingDTMFTone                     |interfacesEstablished          |MediaExchange(1,100,147,15)      |SIPInterface(1,100,77,23)        |1,100,10,1.4702^^*            |[R:N-H:0,N:0,L:0,V:0,Z:0,D:0] tone=6 CI=0 confId=77 passthruPartyID=0xa917705 isMTPPassingThru2833=F

00925351.000 |20:30:23.093 |SdlSig   |MXOutgoingDTMFTone                     |sessionEstablished             |MTPAgenaInterface(1,100,249,4)   |MediaExchange(1,100,147,15)      |1,100,10,1.4702^^*            |[R:N-H:0,N:0,L:0,V:0,Z:0,D:0] tone=6 CI=0 confId=77 passthruPartyID=0xa917705 isMTPPassingThru2833=F

00925351.001 |20:30:23.093 |AppInfo  |DET-AgenaInterfaceBase-(4)::getPartyIdForAgena, numofportopened=0, mediaType=1, fcodec=0

00925351.002 |20:30:23.093 |AppInfo  |DET-MTPAgenaInterface-(4)::setPartyIdFromRSVPAgentInfo, nPortopened=0, mediaType=1, fcodec=0

00925352.000 |20:30:23.093 |SdlSig   |MXOutgoingDTMFTone                     |waiting                        |MediaTerminationPointControl(1,100,139,3) |MTPAgenaInterface(1,100,249,4)   |1,100,10,1.4702^^*            |[R:N-H:0,N:0,L:0,V:0,Z:0,D:0] tone=6 CI=30384064 confId=16793218 passthruPartyID=0x1000008 isMTPPassingThru2833=F

00925352.001 |20:30:23.093 |AppInfo  |MediaTerminationPointControl(3)::star_MediaExchangeOutgoingDTMFTone tone=6, conferenceID=16793218, passthruID=16777224

00925352.002 |20:30:23.093 |AppInfo  |MediaTerminationPointControl(3)::star_MediaExchangeOutgoingDTMFTone TCPPid = [] myIP: 0x100a8c0 ( conferenceID=16793218, passthruPartyID=16777224, tone=6

Simon Birtles

I have been in the IT sector for over 20 years with a primary focus on solutions around networking architecture & design in Data Center and WAN. I have held two CCIEs (#20221) for over 12 years with many retired certifications with Cisco and Microsoft. I have worked in demanding and critical sectors such as finance, insurance, health care and government providing solutions for architecture, design and problem analysis. I have been coding for as long as I can remember in C/C++ and Python (for most things nowadays). Locations that I work without additional paperwork (incl. post Brexit) are the UK and the EU including Germany, Netherlands, Spain and Belgium.