Have CIPC 2.1(3) while connecting to Unity 5.0(1): Unity doesn't apprehend DTMF user input at all.
Then I got CIPC traffic dump and saw DTMF are generated both RTP-2833 and SIP NOTIFY messages.
Unity answeres "I have not hear your input ..." or something.
No problem occurs when convert CIPC to SCCP code.
If dump or anything is needed let me know, I'll attach.