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.