My organization recently upgraded our CUCM and CUC from 10.5 to 12.5. We have a mix of 7900 series phones (running on SCCP) and 7800/8800 series phones (running on SIP). Prior to the upgrade, DTMF worked on all phones. After the upgrade, DTMF tones on the SIP phones no longer work for outgoing calls to the PSTN. However, DTMF works perfectly fine from all of the SCCP phones. Also, there are no issues with DTMF (for both SIP and SCCP phones) when retrieving voicemail from Unity. Both PSTN and Unity are connected to CUCM via SIP trunks.
Is there anything different in CUCM 12.5 that would cause DTMF to suddenly stop working for the SIP phones? Perhaps there is a new setting that needs to be configured?
Our setup is as follows:
CUCM ---[SIP Trunk]--- CUBE Gateway (Cisco 2921) ---[SIP dial peers]--- PSTN
All of the SIP phones have Media Termination Point Required checked off in CUCM
On the CUBE, all dial peers include the following config: dtmf-relay rtp-nte sip-kpml. Also, the sip settings under voice service voip includes the early-offer forced config
