This TS specifies the procedures used at the radio interface for normal operation, registration, erasure, activation, deactivation, interrogation and network invocation of call offering supplementary services.
The following supplementary services belong to the call offering supplementary services and are described in this TS:
Call forwarding unconditional (CFU);
Call forwarding on mobile subscriber busy (CFB);
Call forwarding on no reply (CFNRy);
Call forwarding on mobile subscriber not reachable (CFNRc).