I recently upgraded from CUC 10.5 to 11.5. After upgrade there is no DTMF being sent from IP Phones registered with CUCM (also upgraded from 10.5 to 11.5). The integration is SIP. The Unity Connections work fine with CUCM on 10.5. I have tried all sorts of configurations but no luck. The only way it will work is if I tick the MTP required on the SIP Trunk to Unity Connections. However I don't want to use MTP. Is there anything change in CUC 11.5 for this to occur?
I have tried various DTMF options however it is not standard Unity Connections configuration. All the configurations should be retained from the upgrade. Why does it all of a sudden need MTP going from 10.5 to 11.5