1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 - TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!).4%.!.#%G0 ).42/$5#4)/.G0G0!.$G0G0%.%2!,G0G002).#)0,%335“G13#/.42/,G0G034!4)/.3)45G134G0G0RecommendationG0G0- (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation M.90 was published in Fascicle IV.1 of
2、 the Blue Book. This file is an extract from theBlue 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 (see below).2 In this Recommendati
3、on, 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 means, electronic ormechanical, includi
4、ng photocopying and microfilm, without permission in writing from the ITU.Fascicle IV.1 - Rec. M.90 1Recommendation M.90Fascicle IV.1 - Rec. M.90SUB-CONTROL STATIONS1 Definition of sub-control stationA sub-control station is a point within the general maintenance organization which fulfils the sub-c
5、ontrolresponsibilities of the circuit, group, supergroup, etc. digital section, assigned to it.2 Appointment of sub-control stationsThe following principles apply to: every international circuit (circuit sub-control station), for whatever purpose (telephony, telegraphy,sound-programme, data transmis
6、sion, etc.). (See in particular Recommendations N.5 1 in connectionwith sound-programme circuits and N.55 2 in connection with television circuits); every international digital block, digital path, group, supergroup, mastergroup or supermastergroup(digital block sub-control station, digital path sub
7、control station, group sub-control station, supergroupsub-control station, etc.); every line link, every regulated line section and every digital line section (line link sub-control station,regulated line section sub-control station, digital line section sub-control station) using a symmetric pairl
8、ine, a coaxial line, an optical fibre or a radio-relay link.The technical service of the Administration concerned designates the station that is to act as a sub-controlstation in its country and informs the technical service of the country responsible for the control station accordingly.2.1 Terminal
9、 sub-control stations2.1.1 Terminal sub-control stations for circuitsFor each circuit a terminal circuit sub-control station is appointed in accordance with Recommendations M.724and M.1013 3 as appropriate.For unidirectional constituted circuits the terminal station at the sending end should be the
10、terminal circuitsub-control station. In particular, in the case of sound-programme or television circuits, the terminal ISPC or ITC at thesending end should be the terminal sub-control station. (See Recommendations N.5 1 and N.55 2.)2.1.2 Terminal sub-control stations for digital blocks, digital pat
11、hs, groups, supergroups, etc.At the two ends of a digital block, digital path, group, supergroup, etc., the terminal stations are designated asterminal digital block, digital path, group, supergroup, etc., sub-control stations for the direction of transmission forwhich they are not the digital block
12、 digital path, group, supergroup, etc., control station.2.1.3 Terminal sub-control station for a digital section, line link or a regulated line sectionAt the two ends of a digital section, line link or a regulated line section, the terminal stations are designated asterminal digital section, line l
13、ink or regulated line section sub-control station for the direction of transmission for whichthey are not the digital section, line link or regulated line section control station.2.2 Intermediate sub-control stations2.2.1 Intermediate sub-control stations for circuitsIn transit countries in which a
14、circuit is brought to audio frequencies or 64 kbit/s, etc., an intermediate circuitsub-control station is appointed at a suitable point for each direction of transmission. It is left to the country concerned tochoose: where this point shall be; whether the sub-control functions for the two direction
15、s of transmission are vested in one station or twostations (see Figure 1/M.90); whether, as may be desirable in the case of a large country, each direction of transmission has more thanone circuit sub-control station per transit country.2 Fascicle IV.1 - Rec. M.90d01-scFIGURE 1/M.90.D012.2.2 Interme
16、diate sub-control stations for paths and linksIn general, for digital paths and analogue links, in transit countries in which the path or link concerned appearsin its characteristic bit rate or in its basic frequency range, an intermediate sub-control station is appointed for eachdirection of transm
17、ission. The countries concerned have the same prerogatives as those indicated above for circuits(see 2.2.1 and Figure 1/M.90).2.2.3 Intermediate sub-control stations for regulated line sectionsIn transit countries, a regulated line section intermediate sub-control station is appointed for each direc
18、tion oftransmission, the same discretion as for circuits being given to the country concerned (see 2.2.1 above andFigure 1/M.90).2.3 Combination of functionsAny, or all, of the above functions may be vested in one station, depending on the arrangements in the countryconcerned.3 Responsibilities of s
19、ub-control stations for circuitsSee Recommendations M.724 and M.1013 3 concerning automatic public telephone circuits, leased circuitsand special circuits, respectively. See also Recommendations N.5 1 and N.55 2 in connection with sound-programmeand television circuits.4 Responsibilities of sub-cont
20、rol stations for groups, supergroups, digital blocks, digital paths, etc.The responsibilities of sub-control stations are, for the sections which they control, similar to those given inRecommendation M.80 for control stations, but in addition they include: cooperating with the control stations and o
21、ther sub-control stations in locating and clearing faults; setting up and maintaining that part of the digital path, group link, supergroup link, mastergroup link, orregulated line link between the through-connection stations nearest to the two frontiers; seeing that the transmission on the national
22、 section with which they are concerned is within the prescribedlimits; reporting to the control station all relevant details concerning the location and subsequent clearance offaults; keeping the necessary records on lining-up (analogue transmission) or initial measurements (digitaltransmission), fa
23、ult location and fault clearing for the section for which they are responsible.In addition to the above responsibilities, an intermediate sub-control station (in a transit country) is responsiblefor initiating fault localization tests on the sections it controls in response to reports from other con
24、trol or sub-controlstations.References1 CCITT Recommendation Control and sub-control stations for sound-programme circuits, connections, etc.,Vol. IV, Rec. N.5.2 CCITT Recommendation Organization, responsibilities and functions of control and sub-control ITCs andcontrol and sub-control stations for international television connections, links, circuits and circuit sections,Vol. IV, Rec. N.55.3 CCITT Recommendation Circuit sub-control station for leased and special circuits, Vol. IV, Rec. M.1013.
