scope:

This European Telecommunication Standard (ETS) specifies procedures to support supplementary services for Broadband Integrated Services Digital Network (B-ISDN) Capability Set 1 (CS1) applications defined for the pan-European B-ISDN as provided by the European public telecommunications operators by means of the Signalling System No.7 protocol for the B-ISDN User Part (B-ISUP).

Additional protocol requirements, which have to be specified in the case where services are provided to the user via a telecommunication network that is not a B-ISDN, are not part of this ETS.

Although this ETS applies only to the international section, the specification of functions, formats and codes of messages and signals, and actions performed at originating and destination local exchanges are retained. All formats, codes and procedures marked for national use are included for informative purposes only. At transit nodes, B-ISUP supports the narrowband ISDN User Part (ISUP) services depicted in ISUP version 2 as defined in ETS 300 356-1 to ETS 300 356-19 ([1] to [18]).

In the case where a national signalling system behaves differently, the international gateway exchange is to support both the concerned national and the international network and the services and equipment supported by both the concerned national and international network.