scope:

The present document defines the stage one of the Message Waiting Indication (MWI) supplementary service for the pan-European Integrated Services Digital Network (ISDN) as provided by European public network operators. Stage one is an overall service description from the user's point of view (see CCITT Recommendation I.130 [4]), but does not deal with the details of the human interface itself.

This ETS defines the interworking requirements of private ISDNs with the public ISDN.

Interactions with supplementary services not listed in clause 8 are outside the scope of this ETS.

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 the 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.

This ETS is applicable to the stage two and stage three standards for the ISDN MWI supplementary service. The terms "stage two" and "stage three" are also defined in CCITT Recommendation I.130 [4]. Where the text indicates the status of a requirement (i.e. as strict command or prohibition, as authorization leaving freedom, or as a capability or possibility), this shall be reflected in the text of the relevant stage two and stage three standards.

Furthermore, conformance to this ETS is met by conforming to the stage three standard with the field of application appropriate to the equipment being implemented. Therefore, no method of testing is provided for this ETS.