DTMF digits through Expressway

[Gordon Ross]

I'm running Expressway-C&E V8.7 with CUCM 11.0. The Expressways are configured for SIP/H.323 internetworking. The setup is basically as per the VCS/CUCM deployment guide.

When a H.323 video endpoints calls in to CUCM via Expressway, once the call is established, DTMF tones are transmitted through to CUCM just as tones and not being recognised as DTMF digits.

Any suggestions as to how to troubleshoot/resolve this?

Thanks,

GTG

[Patrick Sparkman]

Do you have the DTMF on the Expressway SIP Trunk set to use RFC 2833 per the Expressway and CUCM via SIP Trunk Deployment Guide (CUCM 8,9,10,11 and X8.7)?  The Understanding SIP DTMF Options supported by CUCM might be helpful as well.

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[Gordon Ross · Accepted solution]

I found the problem. The video endpoint and Expressway use different, but incompatible, H.323 options for transmitting out-of-band DTMF information. There is no solution to this :-(

GTG