scope:

This first part of EN 300 196 specifies the functional protocol for the pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications operators for the application to a range of supplementary services at the T reference point or coincident S and T reference point (as defined in ITU-T Recommendation I.411 [3]) by means of the Digital Subscriber Signalling System No. one (DSS1) protocol. The functional protocol is based on the use of the Facility information element and the FACILITY message, as well as on other specific functional messages specified in subclause 11.1. The protocol is symmetrical, and is applicable to both the basic and primary rate access structures. To be functional this protocol requires knowledge of supplementary services supported by the user equipment. This facilitates user equipment operation without human intervention by defining semantics for the protocol elements which user equipment can process on its own.