Hi

We are testing interoperation against both CUCM 7.1 and 8.5(but do not have 8.5 yet).

But we are having some trouble invoking MOH when our gateway is registering as a 3rd party SIP phone and initating a hold (we have the same issue with snom 300s too).  The same operation performed by a 7941/7960 (SIP) the held party receives music on hold from the CUCM.

The call signalling does appear to operate correctly, in that the hold reinvite sent is responded to, and the held party is commanded by the CUCM to renegotiate the RTP behaviour, after which the resume is also processed correctly and the two RTP is renegotiated.  But this is missing the music on hold that is present if a Cisco IP Phone intiates the hold.

We would like to ask if there are any special configuration options that need to be enabled to allow 3rd party SIP Phones to intiate a hold and the held party receive MOH until resumed.
 
Any help much appreciated!