Is there a way to send the dtmf attached on the sip invite, or in somewhere in the signaling process on an enbloc string like 81 1111 1111 - 1234 (where 81 1111 1111 is our did, and the 1234 is the dtmf)?
IP Phone firmware will interpret a comma as a pause with digits following to be sent after the call connects and the timer expires. For example, 8111111111,1234. You can use multiple commas if needed. This will not work on CUCM Route/Translation patterns.