DTMF problem

[asp-pts01]

Hello!

We have CUCM connected to VCS through SIP trunk, and VCS connected to ISDN GW MSE8321 through H323. 8321 also connected to Alcatel ISDN. There is IVR on CUCM/CUC.  IVR works fine on CUCM and VCS VoIP users. But users, called from ISDN to CUCM can't navigate on CUC IVR menu. When some user from mobile/PSTN phone calls to CUCM user and send DTMF, the CUCM user can listen DTMF tones. This check confirms that DTMF codes pass from ISDN to CUCM. I tried to change DTMF Signaling Method on CUCM-VCS SIP trunk. What else could be the problem?

[Anthony Holloway]

The fact that you can hear the DTMF tones is bad. I know, that sounds counter intuitive, but in the IP World, DTMF "should" be passed as data and not as audio. It sounds like you'll need some DSPs in the middle to convert from inband audio to a DTMF Relay technology, preferably an Out of Band one, so that your CUCM side can properly interwork the DTMF between different systems (E.g., UCCX is CTI based, CUC is RFC2833 or SCCP or SIP).