Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. One (DSS1) Protocol; Data Link Layer; Part 2: General Protocol Specification (ITU-T Recommendation Q.921 (1993)@ Modified)
This European Telecommunication Standard (ETS) describes in general terms the link access procedure of the Digital Subscriber Signalling System No. one (DSS1) protocol when used in the pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications operators@ or in a Private Telecommunication Network (PTN)@ at the T reference point or the S reference point or the coincident S and T reference point (as defined in ITU-T Recommendation I.411 [15]). Annex ZA of this ETS describes in general terms the link access procedure for use in a symmetrical application between two Private Telecommunication Network eXchanges (PTNXs) at the Q reference point (see ETS 300 475-1 [14]). Conformance to this ETS is met by conforming to the specific protocol standards for individual applications. Therefore@ no separate method of testing is provided for this ETS. The field of application of this ETS is determined by specific protocol standards for individual applications.