/mcpInteraction Feature CallBack would work normally in case or when DND-Reject is set to Off at the originating or the terminating end. The behavior differs only when DND-Reject is set to On. • DND-Reject On on Originating end—User A calls User B and invokes Call Back. User A goes on DND-R. After User B is available, the CallBack notification will still be displayed to User A. That is, user will still be notified with the availability of the other party irrespective of the DND status. • DND-Reject On on Terminating end—User A calls User B, and User B has set DND-Reject to On. User A will get a fast busy tone. User A can initiate CallBack on a busy endpoint. If User B is still on DND-Reject and goes Offhook and Onhook, User A will get a notification “User B is available now but on DND-R”, and it will not show the Dial option. If User A does not choose to cancel, CallBack will still monitor User B until User B sets DND-Reject to Off. Do Not Disturb (DND) When a Cisco Extension Mobility user logs in or logs out, any active call completion that is associated with Call Back is automatically canceled. If a called phone is removed from the system after Call Back is activated on the phone, the caller receives a reorder tone after pressing the Dial softkey. The user may cancel or reactivate Call Back. Cisco Extension Mobility Call Back Restrictions Restriction Feature The Call Back feature does not work for video calls when the call is placed between two Unified CM clusters that are connected via CUBE with qsig-enabled SIP trunks. For additional detail, see CSCun46243. Call Back with video across CUBE Call Back is not supported over SIP trunks but is supported over QSIG-enabled SIP trunks. SIP Trunks Call Back only supports spaces and digits 0 through 9 for the name or number of the calling or called party. To work with CallBack, the name or number of the calling or called party cannot contain a pound sign (#) or asterisk (*). Supported characters for name or number of calling or called party You cannot activate Call Back if you forward all calls to Voice-Messaging System. Voicemail Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs 252 Placing Calls Call Back Restrictions