Yealink CP960 User Manual page 207

Enter the SIP URI (e.g., sip:moh@sip.com) in the Music Server URI field.
3.
Click Confirm to accept the change.
4.
When you place a call on hold, music will be played to the held party.
For this feature to function, all involved parties cannot use encrypted RTP (SRTP).
Note
Music on hold server is configurable via web user interface only.
Advanced Phone Features
207