scope:

The present document specifies the supplementary services Call Forwarding Unconditional (CFU), Call Forwarding Busy (CFB), Call Forwarding on No Reply (CFNRy) and Call Forwarding on Not Reachable (CFNRc) which are applicable to various basic services supported by TETRA SwMIs. Basic services are specified in EN 300 392-2 [4]. SS-CFU, SS-CFB, SS-CFNRy and SS-CFNRc are supplementary services which apply during call establishment providing a forwarding of an incoming call to an other destination than the original destination defined by the calling user under different conditions (busy, no reply or not reachable) or under no condition (unconditional). The present document is applicable to circuit mode TETRA V+D tele-services and bearer services. The present document is also applicable to TETRA Short Data Service (SDS), but limited to the supplementary service Call Forwarding Unconditional (CFU). Man machine interfaces and charging principles are outside the scope of the present document. The present document specifies also the SS-CF invocation counter, which is applicable to various basic services supported by TETRA networks.