With call forwarding, the PBX or the end device forwards an incoming call to an alternative phone number further. Call forwarding can typically be based on one or more of the following conditions: Forward on busy (CFB), forwarding if unavailable (CFNR) or forwarding if no reply (CFU). Since an outgoing call is initiated by the PBX or terminal device for call forwarding, the number of the forwarder is displayed for the forwarding destination if the forwarder is not responsible for number transmission without screening (clip no screening) is eligible.
