scope:

The present document defines the stage one of the Outgoing Call Barring-User Controlled (OCB-UC) supplementary service for the pan-European Integrated Services Digital Network (ISDN) as provided by European telecommunications operators. Stage one is an overall service description from the user's point of view (see CCITT Recommendation I.130 [1]), but does not deal with the details of the human interface itself. The present document defines the interworking requirements of private ISDNs with the public ISDN. In addition the present document specifies the base functionality where the service is provided to the user via a private ISDN. The present document does not specify the additional requirements where the service is provided to the user via a telecommunications network that is not an ISDN but does include interworking requirements of other networks with the public ISDN. Interactions with supplementary services not listed in clause 7 and other services not listed in clause 8 are outside the scope of the present document.