This document specifies the Call Forwarding supplementary services: - Call Forwarding Unconditional (SS-CFU); - Call Forwarding Busy (SS-CFB); - Call Forwarding No Reply (SS-CFNRy); - Call Forwarding Not Reachable (SS-CFNRc). which are applicable to various basic services supported by TETRA SwMIs. Basic services are specified in ETS 300 392-2 [4].