1、CCITT FASCICLE IV.3 * W 4862571 0505432 7 ANNEX A (to Recommendation M.555) Designation information of international digital blocks and paths A.l Designation The designation is according to Recommendation M.140, $5 9 and 10. A.2 Related information The additional information on digital blocks, etc.
2、is covered by the following items: RI 1. RI 2. RI 3. RI 4. RI 5. RI 6. RI 7. RI 8. RI 9. RI 10. RI 11. RI 12. RI 13. RI 14. RI 15. RI 16. urgency for restoration; terminal countries; carriers names; control and subcontrol station(s); fault report points; routing; association; equipment information;
3、use; transmission medium; (empty item, use “ - ”); only for the mixed analogue/digital network: end-to-end information; bit rate; occupancy (for blocks); actual number of channels (for primary blocks); clocking information (for blocks); direction of transmission (for unidirectional blocks). The vari
4、ous items will be dealt with in $ 12 of Recommendation M.140. References CCITT Recommendation Protection against the effects of faulty transmission on groups and circuits, Vol. VI, Rec. Q.33. CC1- Recommendation Error performance measuring equipment for digital systems, Vol. IV, Rec. 0.151. integrat
5、ed services digital network, Vol. III, Rec. G.821. i 2 3 CCIT Recommendation Error performance of an international digital connection forming part of an Recommendation M.556 SETTING UP AND INITIAL TESTING OF DIGITAL CHANNELS ON AN INTERNATIONAL DIGITAL PATH OR BLOCK The definition of a digital chann
6、el is given in Recommendation M.300. Procedures in CCIT Recommen- dation M.555 for bringing-into-service digital blocks and digital paths are adequate to ensure satisfactory operation of digital channels which are provided on the respective digital blocks or paths. No specific tests are required for
7、 individual digital channels. Where digital channels are terminated at each end by mixed analogue/digital terminals, Administrations may, with bilateral agreement, choose to apply a procedure similar to that in CCITT Recommendation M.470, to test from each audio input to each audio output. This procedure is an alternative to the mixed analogue/digital terminal circuit section line-up procedure in CCIT Recommendation M.580. I -, 333 7 _7 Fascicle IV.l - Rec. M.556
