1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU MAINTENANCE OF INTERNATIONAL TRANSMISSION CIRCUITS SOUND-PROGRAMME AND TELEVISION N.55 (03/93) ORGANIZATION, RESPONSIBILITIES CONTROL INTERNATIONAL TELEVISION CONTROL STATIONS FOR INTERNATIONAL TELEVISION CON
2、NECTIONS, LINKS, CIRCUITS AND CIRCUIT SECTIONS AND FUNCTIONS OF CONTROL AND SUB- CENTRES AND CONTROL AND SUB- ITU-T Recommendation N.55 (Previously “CCITT Recommendation”) ITU-T *RECMN*N-55 93 4862591 05895Yb 518 9 FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent orga
3、n of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), w
4、hich meets every four years, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T Recommendation N.55 was revised by the ITU-T Study Group IV (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a
5、 consequence of a reform process within the International Telecommunication Union (ITU), the CCIT ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB ha
6、ve been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of thi
7、s Recommendation will contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 All rights reserved. No part of t
8、his publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. CONTENTS Abbreviations 1 Organization . 2 Responsibilities 4 Pre-transmission procedures 3 Functions 5 7 8 9 Timing t
9、he international television transmission . Fault location and handling Record keeping and monitoring for charging purposes . Responsibilities of control and sub-control stations for multiple destination transmissions 9.2 Send reference stations . 9.3 Additional responsibilities of control stations 1
10、0 International television transmissions for television receive-only stations (TVROs) not related to an ITC References . Recommendation N.55 (03/93) Page 1 1 1 2 3 3 4 5 6 6 7 7 7 i ITU-T *RECflN*N.55 93 W 4862591 0589548 390 ABSTRACT This Recommendation outlines the responsibilities and functions a
11、ssociated with the control and sub-control stations involved with an international television connection, including: - the establishment of the connection; - - fault location; start and stop times and record keeping for charging purposes; - TVROS. Keywords Charging times, control, establishment, fau
12、lt location, international television centres, sub-control, television, TVRO. 11 Recommendation N.55 (03/93) Recommendation N.55 ORGANIZATION, RESPONSIBILITIES AND FUNCTIONS OF CONTROL AND SUB-CONTROL INTERNATIONAL TELEVISION CENTRES AND CONTROL AND SUB-CONTROL STATIONS FOR INTERNATIONAL TELEVISION
13、CONNECTIONS, LINKS, CIRCUITS AND CIRCUIT SECTIONS (Published in 1964; revised in 1968, 1972,1980,1988,1993) Abbreviations For the purposes of this Recommendation, the following abbreviations apply: TVRO Television receive-only station ITC International television centre UTC Coordinated universal tim
14、e FRC Fault reporting centre 1 Organization 1.1 involved. The international television link is in all cases the sole responsibility of the telecommunication Administrations 1.2 The national television circuits at the ends of the link may be the responsibility of either the telecommunication Administ
15、ration or the broadcasting organization of the two together, depending on local arrangements in each particular country. 1.3 The ITC at the receiving end (country C in Figure 2M.51 3) is normally the control station for both the international television link and the international television connecti
16、on and is referred to as the control ITC. The choice of the station which is to have this function is left to the discretion of the Administration concerned. 1.4 the international television link and are referred to as intermediate sub-control ITCs. The intermediate ITCs, where the international cir
17、cuit appears at video frequencies, are sub-control stations for 1.5 Circuit sections, including satellite sections, also have control and sub-control stations. From the standpoint of overall control arrangements for an international television link, a station controlling a circuit section is referre
18、d to herein as an intermediate sub-control station. 1.6 The ITC at the sending end (country A in Figure 2M.51 3) is normally the sub-control station for both the international television link and the international television connection. It is also referred to as the terminal sub-control ITC. However
19、, the choice of the station which is to have this function is left to the discretion of the Administration concerned. 2 Responsi biii ties 2.1 The control ITC is responsible to the broadcasting organization (receive) for the satisfactory performance of the overall international television connection
20、. When an international television connection does not include a satellite section, the control ITC should exert control through intermediate sub-control ITCs and stations, on that portion of the international television connection extending from the terminal sub-control ITC to the broadcasting orga
21、nization (receive). When an international television connection does include a satellite section, the control ITC should exert control through intermediate sub-control ITCs and stations, on that portion of the international television connection extending from the transmitting earth station to the b
22、roadcasting organization (receive). Recommendation N.55 (03/93) 1 ITU-T *RECMN*N-55 93 4862593 0589550 “47 = 2.2 When an international television connection does not include a Satellite section, control of that portion of the international television connection extending from the broadcasting organi
23、zation (send) to the terminal sub-control ITC should be exerted through the terminal sub-control ITC. When an international television connection does include a satellite section, control of that portion of the international television connection extending from the broadcasting organization (send) t
24、o the transmitting earth station should be exerted through the terminai sub-control ITC. In each case, the terminal sub-control ITC is, in turn, responsible for the satisfactory performance of that portion of the connection over which the terminai sub-control ITC has control responsibility; the term
25、inal sub-control ITC should co- ordinate the activities of any intermediate sub-control ITCs and stations, both prior to and during the transmission, thus assisting the control ITC and keeping that office informed of developments. 2.3 The received earth station is the control station for the satelli
26、te circuit section. Reference to the control station for the satellite circuit section is intended to apply to the station, or portion of the station, manned by personnel of the satellite operator. 2.4 Any intermediate sub-control ITCs, and other intermediate sub-control stations, are responsible fo
27、r the satisfactory performance of their respective circuits and circuit sections. In the operation of an international television connection, any sub-control ITCs and stations which are intermediate are responsible to either the terminal sub-control ITC or the control ITC, depending upon their locat
28、ion in the overall connection. 3 Functions 3.1 should perform the following functions: All stations which are designated as control and sub-control stations on an international television connection - ensure that sections under each respective control are condition for service and connected into the
29、 international television connection at the appropriate time; - time the start and conclusion of the transmission in accordance with clause 5 below; - keep complete and accurate records of all station activities pertaining to the international television transmission. This should include timing and
30、recording service impairment observed or reported, and taking corrective action under the direction of the control or terminal sub-control ITC; - prepare and forward prescribed reports. 3.2 additional functions: Control and terminal sub-control ITCs on an international television connection should p
31、erform the following - verify the scheduling of the television transmission and the availabiliv of information necessary to furnish it; - perform and Co-ordinate, as required, prescribed pre-transmission line-up tests; - check the satisfactory receipt, by the broadcasting organization (receive), of
32、the test programme originated by the broadcasting organization (send); - ensure that the international television connection is handed over to the broadcasting organizations at the scheduled time. 3.3 In order to perform the above functions satisfactorily it is essential that adequate and direct com
33、munications be available between terminal ITCs during the line-up and service periods. It is preferable that such communications be provided by direct service circuits (as those specified in Recommendation M.lOO i), the requirement for television being analogous to the requirements for the service c
34、ircuits of the telephone and telex networks. In those instances where permanent direct service circuits are not provided and the television service is of an infrequent nature, it will be the responsibility of the control ITC to initiate action for the provision of an adequate means of communications
35、. Use of the public telephone network or electronic text systems should be encouraged in such instances. 2 Recommendation N.55 (03/93) ITU-T *RECMN*N*55 93 m 48b259L 0589553 985 m 4 Pre-transmission procedures 4.1 At some time prior to the scheduled start of television transmission, preferably the d
36、ay before but not less that two hours prior to the start of service, the control ITC should contact the terminal sub-control ITC and the appropriate intermediate sub-control ITCs or stations, over which it exercises control and confirm that they have the transmission schedule and sufficient informat
37、ion to furnish the service. Similarly, the terminal sub-control ITC should contact the intermediate sub-control ITCs or stations over which it exercises control to verify their readiness. 4.2 The control and sub-control ITCs should initiate circuit section line-up tests for which they are directly r
38、esponsible. The test should be completed far enough in advance of the scheduled time at which the connection is to be handed over to the broadcasting organization (point H in Figure 1B.54 4) to assure completion by that time of the operations given in 4.3. During this same period the control station
39、 for any satellite circuit section should perform line- up tests as prescribed by the responsible authority. The test recommended for terrestrial circuit sections and ITC-to-ITC links are those detailed in Recommendation N.62 5. 4.3 Immediately upon conclusion of the circuit section tests, the contr
40、ol ITC, with the cooperation of the terminal sub-control ITC, should verify that the international television link is continuous between these terminal ITCs and should then proceed to perform overall line-up tests as detailed in Recommendation N.62 5. 4.4 Upon completion of the overall tests, and if
41、 possible 2 or 3 minutes prior to the scheduled start of the transmission from the broadcasting organization (send), the control and sub-control ITCs should establish the connection to the broadcasting organizations and check the test programme between them. Checking the test programme consists of v
42、erifying the satisfactory receipt, from the standpoints of quality and level, by the broadcasting organization (receive) of test material originated by the broadcasting organization (send). The sub-control ITC should request this transmission of test material from the broadcasting organization (send
43、), as necessary, and should verify that the material is of suitable quality and level at its location. The control ITC should also check for suitable quality and level at its location. After it is determined that the test programme check is satisfactory, the connection should be handed over to the b
44、roadcasting organizations. 5 Timing the international television transmission 5.1 times of start and conclusion of the transmission, in UTC. The control ITC and terminal sub-control ITC of the international television connection should record the 5.2 The starting time to be indicated is defined belo
45、w: - If the intemational television transmission is established for the broadcasting organization at the scheduled starting time indicated on the planning schedule, or before that time without any request for doing so from the broadcasting organization, it is the scheduled starting time indicated on
46、 the planning schedule. - If the intemational television transmission is established for the broadcasting organization at a certain time before the planning schedule starting time, because the broadcasting organization had wished so, and the Administration had agreed, it is the time when the transmi
47、ssion is actually established for the broadcasting organization. If the transmission is not ready at the scheduled time, and is established later, it is the time when the transmission is established for the broadcasting organization. In the case of transmissions which are not on the planned schedule
48、, but verbally demanded and accepted by the Administration, and established a little later, it is the time when the transmission is established for the broadcasting organization. - - 5.3 organization (receive) (end of chargeable duration - sometimes called the Good-night time). The concluding time o
49、f the service is the time at which the connection is released by the broadcasting When satellites are used to establish international television connections, the start of service and end of service times for the space segment are specified in accordance with procedures of the satellite system operating authority. For example, the receive earth station must be notified in order to comply with the satellite system operating authority requirements for space segment deactivation. The corresponding chargeable time only applies to the space segment and may be different from the one of t
