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DTMF between SIP and GW problem

Hello, I have CUCM 8.6 connecting via a SIP trunk to a 2801 gateway router and then out to the PSTN via an ITSP SIP proxy.

The calls are find but DTMF is not working. I am using SCCP 7940 phones.

I have tried adding "dtmf-relay h245-alphanumeric" to my gateway dial peers.

I have tried adding "voice-class sip dtmf-relay force rtp-nte" to my gateway dial peers.

I have tried choosing both of the options under "Required Field" within CUCM trunk configuration.

I have tried selecting the "Media Termination Point Required" option within the CUCM Trunk configuration.

I tried selecting "Early Offer support for voice and video calls (insert MTP if needed)" within the SIP profile for the trunk.

No luck.

Can someone please tell me what I should try next ?

Thanks kindly.

  • IP Telephony
Cisco Employee

DTMF between SIP and GW problem

Have you tried configuring rtp-nte on the outbound dial peer ot CUCM and checking the MTP required option on the CUCM SIP Trunk at the same time?

1.    enable

2.    configure terminal

3.    dial-peer voice number voip

4.    session protocol sipv2

5.    dtmf-relay rtp-nte

6.    rtp payload-type nte number comfort-noise [13 | 19]

7.    exit