scope:

This first part of ETS 300 664 specifies the stage three of the Calling Line Identification Restriction (CLIR) supplementary service for the pan-European Broadband Integrated Services Digital Network (B-ISDN) as provided by European public telecommunications operators at the T_B reference point or coincident S B and T_B reference point (as defined in ITU-T Recommendation I.413 [1]) by means of the Digital Subscriber Signalling System No. two (DSS2) protocol. Stage three identifies the protocol and procedures and switching functions needed to support a telecommunication service (see ITU-T Recommendation I.130 [2]).

In addition, this ETS specifies the protocol requirements at the T_B reference point where the service is provided to the user via a private B-ISDN.

This ETS does not specify the additional protocol requirements where the service is provided to the user via a telecommunications network that is not a B-ISDN.

The CLIR supplementary service enables the calling party to prevent presentation of its ISDN number to the called party.

The CLIR supplementary service is applicable to all telecommunication services.

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 CLIR supplementary service, to be attached at either side of a T_B reference point or coincident S B and T_B reference point when used as an access to the public B-ISDN