ÖNORM EN 300392-11-4 V 1.1.1

The present document specifies the Call Forwarding supplementary services: Call Forwarding Unconditional (SS-CFU); Call Forwarding Busy (SS-CFB); Call Forwarding No Reply (SS-CFNRy); and Call Forwarding Not Reachable (SS-CFNRc); which are applicable to various basic services supported by TETRA SwMIs. Basic services are specified in EN 300 392-2 [3]. 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 called (served) user under different conditions (busy, no reply or not reachable respectively) or under no condition (unconditional). The present document is applicable to circuit mode TETRA tele-services and bearer services only for all supplementary services specified in the present document. The present document applies also for SS-CFU to SDS (Short Data Services). The present document also specifies the SS-CF invocation counter, which limits the number of call forwarding that a call request may encounter during call establishment, e.g. to protect the network against indefinite looping. Man machine interfaces and charging principles are outside the scope of the present document.