1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 - TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!).4%.!.#%G0 ).4%2.!4)/.!,G0G04%,%0(/.%G0G0#)2#5)43“2).).G0G0!.G0G0).4%2.!4)/.!,$)4!,G0G0#)2#5)4G0G0).4/G0G03%26)#%)45G134G0G0RecommendationG0G0- (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation M.58
2、5 was published in Fascicle IV.1 of the Blue Book. This file is an extract fromthe Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged
3、 (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any mean
4、s, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle IV.1 - Rec. M.585 1Recommendation M.585Fascicle IV.1 - Rec. M.585BRINGING AN INTERNATIONAL DIGITAL CIRCUIT INTO SERVICE1 OrganizationThe guiding principles for a general maintenance
5、organization for international circuits are given inRecommendation M.70.An international digital circuit may consist of one or more digital circuit sections and digital terminal circuitsections. The types of digital circuit and digital circuit sections for public telephony are described inRecommenda
6、tion M.562.In establishing an international digital circuit, circuit access points define the limits of a circuit. These circuitaccess points are used as the means for performing functional tests including those for channel associated line signalling.2 Transmission tests2.1 Error performanceWhen a c
7、ircuit is brought into service immediately after the digital path(s) over which it is routed arecommissioned, the procedures in Recommendation M.555 (see also Recommendation M.550) are adequate to ensure asatisfactory initial error performance for the circuit.When a circuit is brought into service s
8、ome time after the digital path over which it is routed is commissioned,the circuit control station should ascertain, either directly or from the circuit sub-control station, that the digital path issatisfying the required performance objectives.2.2 Other testsWhen the circuit is to be fitted with a
9、 64 kbit/s device e.g. echo canceller or /A law converter, these shouldfirst be tested before bringing the circuit into service (for echo suppressors and echo cancellers, seeRecommendations M.660 and M.665 respectively).3 Functional testsA speaking test should be made including a subjective check of
10、 the satisfactory operation of echo controldevices.For a circuit using channel-associated signalling, the signal-transmission test facilities available at the controlstation should at least enable a check to be made of the line-signals transmitted between circuit access points, forexample, to verify that the forward signals are followed by the return of the appropriate backward signals.
