1、CEPT T/CS*b8-03*E 2326414 0005267 2 TtCS68-03E Page 1 Recommendation T/CS 68-03 (Brussels 1980, modified in Vienna 1982, Montpellier 194 and Odense 1986) CONNECTIONS, SIGNALLING, CONTROL, CALL HANDLING AND ANCILLARY FUNCTIONS FOR DIGITAL TRANSIT EXCHANGES Recommendation proposed by working Group T/W
2、G 11 “Switching and Signalling” (CS) “The European Conference of Postal and Telecommunications Administrations, recommends that the members of the CEPT, when introducing digital transit exchanges, take account of and give effect to the following specifications on Connections, Signalling, Control, Ca
3、ll Handling and Ancillary Functions for digital transit exchanges.” The reader is referred to CCITT Recommendation Q.503 i, to which this Recommendation is identical, except for the additions and modifications indicated below. The section references (indicated 0) are to 4.503 i. 0 3.2.2; replace by
4、the following: Services carried in a B-channel requiring less than 64 kbit/s for a connection should be switched as 64 kbit/s connections. They should be presented to the exchange as 64 kbit/s channels by digital filling or by being multiplexed to a 64 kbit/s channel before entering the exchange via
5、 a primary of higher frame structure at the transmission/switch- ing interface. The process by which this is performed is not the subject of this Recommendation. Lower bit rate channels multiplexed into A 64 kbit/s stream will be switched as a 64 kbit/s entity. 0 3.3.2; replace by the following: The
6、 exchange should have the capability of establishing semi-permanent connections, taking the following details into account: - semi-permanent connections are carried within PCM multiplexes together with other connections; - they are normally not set up by subscriber control procedures; - they are nor
7、mally not set up during the exchange busy hours; - they pass through the exchange switching network; - the grade of service for semi-permanent connections may differ from that of switched connections and requires Note. The supervision and re-establishment (if provided) of semi-permanent connections in the event of a failure, requires special arrangements in the exchange. O further study. REFERENCE i CCITT Recommendation 4.503. Connections, signalling, control, call handling and ancilIary functions for digital transit exchanges. Edition of September 15, 1986
