1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 8 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU05“,)#G0G0$!4!G0G0.%47/2+342!.3-)33)/. G0G03).!,).G0G0!.$G0G037)4#().#/-/.G0G0#(!%,G0G03).!,).G0G0(b) that common channel signalling offers advantages when used for interexchange signalling in digitalcircuit-
2、switched telecommunication networks;(c) that a need has been established for a standardized common channel signalling system, known as CCITTSignalling System No. 7, for use in international and national applications in single service and multiservices digitalnetworks;(d) that Signalling System No. 7
3、 has been defined with a functional structure clearly separating:- the Message Transfer Part, common for all services and applications, and- User Parts for different services and applications, and in particular, the Data User Part for circuit-switched data applications,unanimously declares the viewt
4、hat common channel signalling for international circuit-switched data applications be in accordance withSignalling System No. 7, i.e.:i) that the data service call control related elements of the signalling system be as specified for the DataUser Part in Recommendation X.61,ii) that the message tran
5、sfer related elements of the signalling system be as specified for the MessageTransfer Part in Recommendations Q.701-Q.707.Note 1 - Signalling System No. 7 including the Data User Part offers a basis for definition of common channelsignalling for national data applications.Note 2 - The implications of the use of the signalling system in multiservices networks and Integrated ServiceDigital Networks (ISDN) providing circuit-switched data services have not yet been fully studied.
