I am using CM 4.1(3) and I want to forward all voice calls to another extension or to voice mail when the phone is not registered with Callmanager, is it available?
This feature was not added until CCM 4.2(1) :(
Cisco Unified CallManager 4.2 introduces the Call Forward Unregistered (CFUR) feature as a way to reroute calls placed to a temporarily unregistered destination phone. The configuration of CFUR consists of two main elements:
When the DN is unregistered, calls can be rerouted to either of the following destinations:
Calls can be sent to voicemail by selecting the voicemail checkbox and configuring the CFUR calling search space to contain the partition of the voicemail pilot number.
A directory number used to reach the phone through the PSTN
From this SRND Guide;
Hope this helps!