scope:

This first part of ETS 300 745 specifies the stage three of the Message Waiting Indication (MWI) supplementary service for the pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications operators at the T reference point or coincident S and T reference point (as defined in ITU-T Recommendation I.411 [7]) by means of the Digital Subscriber Signalling System No. one (DSS1) protocol. Stage three identifies the protocol procedures and switching functions needed to support a telecommunication service (see CCITT Recommendation I.130 [5]).

In addition, this ETS specifies the protocol requirements at the T reference point where the service is provided to the user via an intermediate private ISDN.

This ETS does not specify the additional protocol requirements where the service is provided to the user via a telecommunication network that is not an ISDN but it does include interworking requirements of other networks with the public ISDN.

The MWI supplementary service is provided independently of a call and is therefore applicable to a number of telecommunication services.

Charging principles are outside the scope of this ETS.

The MWI supplementary service enables the network, upon request of a controlling user to indicate to the receiving user, that there is at least one message waiting.

NOTE: The MWI supplementary service is typically used between a mailbox service provider (controlling user) and a user (receiving user) of the mailbox service provided .

Further parts of this ETS specify the method of testing required to identify conformance to this ETS.

This ETS is applicable to equipment supporting the MWI supplementary service, to be attached at either side of a T reference point or coincident S and T reference point when used as an access to the public ISDN.