Content
V8: Preferences → CallForwarding
V10: Identity → Features → CallForwarding → Busy
Menu → Call Features → Call Forwarding → Forward when Busy → Enable Forwarding
8.7.4
<fwd_busy_enabled perm="PERMISSIONFLAGS">VALIDVALUE</fwd_busy_enabled>
If turned on and a call is in progress while a 2nd one is incoming, the second caller is diverted to the number specified.
On/Off
Off