I have a problem with DTMF with SCCP on Phones 7960 and a trunk SIP toward Service provider
1) SCCP Phone 7960 --> CUCM 5.1 --> SIP Trunk --> Service Provider --> IVR
2) SIP Phone 7960 (fmw PC030301) --> CUCM 5.1 --> SIP Trunk --> Service Provider --> IVR
In first scenario the digit sent to the IP Phone are not recognized by IVR in the second scenario yes.
Now, Both SCCP and SIP support RFC2833 - NTE this means that the dtmf are sent inband, into the RTP flow.
Why in the first scenario not working only with SCCP ?
The SIP trunk is without flag "MTP required" and the chioce about the DTMF signaling Method is left to
Is not possible to flag MTP because the customer has restricted request and this option is not conteplate.
Eventually i can move to other IP Phone.