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New Member

DTMF tones on SIP Trunk

We have estabilshed SIP trunk between Cisco CCM and Nortel Meridian. We are able to make calls But DTMF tones are not working on the SIP Trunks.

Cisco CCM 5.0.2

Nortel meridian 81c

Can any one suggest possible solution

New Member

Re: DTMF tones on SIP Trunk

SIP sends DTMF inband (RFC 2833) and you need MTP for this in CCM.

New Member

Re: DTMF tones on SIP Trunk

thanks, this is already configured.

Iam sending the calls to Nortel, nortel receivs G711U In-band DTMF, but where as SIP trunk only supports RFC 2833 RTP.

How can do the transcoding here. i donot have any gateways or routers to do the transcoding, is there any software level transcoding available in ccm.

Re: DTMF tones on SIP Trunk

Would need detailed CCM Traces to determine the exact cause, but you may be hitting CSCsh40465, which is fixed in 5.1(3).

Re: DTMF tones on SIP Trunk

And by detailed CCM traces I mean - detailed CCM traces of a phone registering on the CCM side, and a call out the SIP Trunk.

New Member

Re: DTMF tones on SIP Trunk

Hello, I am facing the same issue with Nortel interop:

Nortel CS1000M --> (IP) Cisco VG --> Call Manager 6

Calls got established but DTMF not transmitted. Do I need to upgrade the VG to CUBE IOS?

Any other options available to solve the interop issue?

Appreciate your feedback.