1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 - TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!).4%.!.#%G0 G0).42/$5#4)/.!.$G0G0%.%2!,G0G002).#)0,%35)$).G0G002).#)0,%3/.G0G04(%G0G0%.%2!,G0G0-!).4%.!.#%/2!.):!4)/.G0G0 in othersonly some of the functions might be combined and carried out from one locat
2、ion. The precise arrangement will dependon the Administration concerned, and the CCITT limits itself to defining the functions of the separate elements, leavingthe manner in which the elements are grouped to be determined by the Administration.1.3 If a country so desires and/or if it judges that the
3、 complexity of its international telecommunications sorequires, the international maintenance organization can be responsible for all types of circuit for which Study Group IVmakes recommendations.2 Types of circuits to be catered forThe types of circuits to be catered for are as follows:public circ
4、uits: telephone circuits, voice-frequency telegraph circuits, phototelegraph circuits, sound-programme circuits, etc.;leased circuits: telephone circuits: point-to-point and multiterminal, voice-frequency telegraph circuits, data circuits: point-to-point and multiterminal, multi-facility circuits, t
5、hat is, phototelegraph plus voice-frequency telegraph; speech plus voice-frequencytelegraph; simultaneous or alternative transmission, phototelegraph circuits, sound-programme circuits, etc.3 Maintenance organizationThe maintenance of international public telephone circuits relies upon the ability o
6、f each Administration tofulfil the various functions and responsibilities noted in the Series M Recommendations. Where such circuits are manual,as opposed to automatic, it is assumed that the Administration will select and provide the relevant elements such as thefault report point (circuit) and the
7、 testing point (transmission) together with circuit control and sub-control stationassignments as appropriate.For automatic circuits all the elements noted in Recommendation M.710 apply.2 Fascicle IV.1 - Rec. M.70Leased and special international circuits require the services of a Transmission Mainte
8、nance Point(International Line) (TMP-IL) which is described in Recommendation M.1014 3. The circuit control and sub-controlfunctions and responsibilities on leased and special international circuits are noted in Recommendations M.1012 1 andM.1013 2 and include a close cooperation with the TMP-IL.For
9、 operations at other levels (group, supergroup, etc.), specific responsibilities are allotted to particularrepeater stations. At each level, maintenance is based on the appointment of a control station and one or moresub-control stations Additional information concerning control and sub-control stat
10、ions follows in RecommendationsM.80 and M.90 and is supplemented by that contained in Recommendations M.1012 1 and M.1013 2, M.723, M.724,N.5 4 and N.55 5.The attention of Administrations is drawn to the need for exchanging contact forms (similar to those formaintenance units for automatic circuits
11、as described in Recommendation M.93) which give telephone numbers, staffinghours, etc. for units involved in the maintenance of leased circuits and the higher order transmission systems.References1 CCITT Recommendation Circuit control station for leased and special circuits, Vol. IV, Rec. M.1012.2 C
12、CITT Recommendation Sub-control station for leased and special circuits, Vol. IV, Rec. M.1013.3 CCITT Recommendation Transmission maintenance point (international line) (TMP-IL), Vol. IV,Rec. M.1014.4 CCITT Recommendation Sound programme control, sub-control and send reference stations, Vol. IV,Rec. N.5.5 CCITT Recommendation Organization, responsibilities and functions of control and sub-control stations forinternational television connections, links, circuits and circuit sections, Vol. IV, Rec. N.55.
