This supplementary service MWI enables a Served User to be sent a Message Waiting Indication and also enables this Message Waiting Indication to be cancelled.
Service specifications are produced in three stages, according to the method described in ETS 300 387. ISO/IEC 15505:2003 contains the stage 1 and stage 2 specifications of SS-MWI. The stage 1 specification (clause 6) specifies the supplementary service as seen by users of PISNs. The stage 2 specification (clause 7) specifies the functional entities involved in the supplementary service and the information flows between them.