In a call forwarding system, a call from a calling party for a called
party is received at a switching device and in response to the received
call the switching device issues a request for call processing
instructions to a control device. The call processing instructions
request is received at the control device and in response to the received
request the control device checks with the destination station to
determine the availability thereof. The control device returns call
processing instructions to the switching device including a telephone
number of the destination station if the destination station is
available. Similarly, the control device returns alternative call
processing instructions to the switching device if the destination
station is not available.