ITU-T U 62-1993 General Requirements to Be Met in Interfacing the International Telex Network with the Fully Automated Maritime VHF UHF Radio System - Telegraph Switching Radiotele.pdf

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1、ITU-T RECMN*U*b2 93 4862593 058B330 B4L = INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU TELEGRAPH SWITCHING RADIOTELEX INTERWORKING U.62 (03/93) GENERAL REQUIREMENTS TO BE MET IN INTERFACING THE INTERNATIONAL TELEX NETWORK WITH THE FULLY AUTOMATED MARITI

2、ME VHF/UHF RADIO SYSTEM ITU-T Recommendation U.62 (Previously “CCITT Recommendation”) FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions

3、 and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendat

4、ions on these topics. ITU-T Recommendation U.62 was revised by the ITU-T Study Group IX (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to exist as of 28 Febru

5、ary 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 Similarly, in this reform process, the CCIR and the IFXB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been

6、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 this Recommendation will contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a r

7、ecognized 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 this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and m

8、icrofilm, without permission in writing from the ITU. ITU-T RECMN*U.b2 93 Y8b2591 0588112 bL4 = CONTENTS Page General . 1 Ship originated calls . 2 Shore originated calls 2 3.1 Interfacing methods 2 3.2 Store-and-forward facilities 2 3.3 MSCs connected to location registers . 2 3.4 MSCs not connecte

9、d to location registers . 4 3.5 Service codes 4 3.6 Maritime answerback code . 4 4 Maritime group calls 4 . Recommendation U.62 (03/93) i ITU-T RECMN*U=b2 73 H 4862571 OS88113 550 Recommendation U.62 GENERAL REQUIREMENTS TO BE MET IN INTERFACING THE INTERNATIONAL TELEX NETWORK WITH THE FULLY AUTOMAT

10、ED MARITIME VHF/UHF RADIO SYSTEM (Malaga-Torremolinos, 1984; revised Helsinki, 1993) The CCIT, considering (a) VHF/UHF radio system be defined; that it is desirable that the interface between the international telex service and the fully automated maritime (b) automated maritime VHFAJHF radio system

11、s; that the CCIR is charged with the task of making recommendations relating to the radio path of the fully (c) maritime VHFAJHF radio systems would be of assistance to the CCIR, that explanation of the detail of the interface between the international telex network and the fully automated unanimous

12、ly recommends that the interface between the international telex network and the automatic maritime VHFAJHF service should be in accordance with the following requirements: 1 General 1.1 In this Recommendation, the term mobile-service switching centre (MSC) is understood to mean the interworking poi

13、nt between the international or national telex network and the maritime VHFAJHF system. The MSC may have access to a junction called the location register which contains the current location of the mobile stations. 1.2 network in one or more ways: Fully automated maritime VHFAJHF radio systems shoul

14、d be capable of interfacing the international telex - in accordance with: i) Recommendation U.l, Signalling conditions to be applied in the international telex service (type A and type B signalling); ii) Recommendation U. 1 1, Telex and gentex signalling on intercontinental circuits used for interco

15、ntinental automatic transit traffic (type C signalling); iii) Recommendation U. 12, Terminal and transit control signalling system for telex and similar services on international circuits (type D signalling); - in accordance with Recommendation F.132, Procedures for use of store and forward faciliti

16、es in the maritime mobile services for ship-originated calls, in accordance with Series F and U Recommendations on international store and forward units. - 1.3 Type D signalling (see Recommendation U.12) and, as a second choice, type C signalling (see Recommendation U.l i) are the preferred signalli

17、ng systems, when they are available within the national boundaries, for the reasons given in Annex AiJ.60. 1.4 The numbering and selection procedures should be in accordance with Recommendation F.121, Recommendation U.62 (03/93) 1 ITU-T RECMN*U-b2 93 4862591 0588114 497 2 Ship originated calls 2.1 W

18、hen accessing a store-and-forward unit, the shipboard subscriber should select, in accordance with Recommendation F.121, one of the access codes 21 or 22 possibly followed by the character “+“ in order to gain access to the store-and-forward facility. 2.2 observed: For direct access to the telex net

19、work, the procedures are given in 3.4F.121. The following points should be 2.2.1 by the MSC. If the end-of-selection character “+“ is not required for technical reasons on the radio path, it must be inserted 2.2.2 Access codes (possibly followed by additional digits) as defined in Recommendation F.1

20、21 for accessing special services or facilities, may be converted by the MSC to an appropriate number in the telex network when the service or facility is terminated at a point in the telex network other than the MSC. 2.3 Any service code generated in the telex network for a particular call should b

21、e returned to the calling ship. 3 Shore originated calls 3.1 Interfacing methods The following interfacing methods are possible: a) b) through a store-and-forward unit associated with one or more MCSs; direct real-time access through an MSC. Here, the following sub-categories may exist: i) ii) MSC c

22、onnected to location registers; MSCs not connected to location registers. The technical solutions, including routing principles, required for each of these interfaces, are given below. 3.2 Store-and-forward facilities 3.2.1 The store-and-forward unit is accessed by normal telex procedures. 3.2.2 sho

23、uld follow the normal procedures defined in Series F and U Recommendations. Procedures for forwarding messages to the store-and-forward unit and for retransmission of such messages 3.2.3 Message should be retained for a period of time as defined in 4.4F.110 3.2.4 currently operating outside their ho

24、me area. The store-and-forward unit may be connected to a location register for routing of calls to ships which are The routing of such calls are described in Annex A. 3.2.5 For other applications of store-and-forward units, see 3.3.6 below. 3.3 MSCs connected to location registers 3.3.1 The technic

25、al arrangement for location registers is outlined in Annex A. 3.3.2 in 3.2.4F.121. A system with MSCs connected to location registers corresponds to the level 3 of operation defined For simplicity, the MSC in which the ship station is permanently registered will be referred to as the home MSC. If th

26、e ship is not in its home area, the MSC in which the ship station is currently located will be referred to as the visited MSC. 2 Recommendation U.62 (03/93) ITU-T RECMN*U=b2 93 4862593 0588115 323 = 3.3.3 They may lead to the following possibilities: The general selection procedures to be used for s

27、etting up calls to ships are given in Recommendation F.121. i) The calling subscribers enters the following number sequence: D1D2(D3)A1A2(A3)MIDX4X5X6 where DlDz(D3) is the Recommendation F.69 destination code of the country in which the home MSC of the called ship is located, AlAz(A3) is the servic

28、e access code in that country and MID ii) when type D signalling is used, the calling line identification procedure should apply. If Control Signalling Code No. 12 is received, the WRU signal answerback procedure defined above should be used. 4.3 Calls from unauthorized subscribers should be cleared

29、 with the service signal NA. 4 Recommendation U.62 (03/93) ITU-T RECMN*U-b2 93 4862591 058BLL7 LTb Annex A Use of location registers in the maritime VHFHF service (This annex forms an integral part of this Recommendation) A.l For the automatic maritime VHFAJHF radiotelephone service, CCIR Recommenda

30、tion 586 describes the procedures to be used on the radio path for updating of location information. A similar procedure would be applicable for the radiotelex service. The location updating is initiated by the ship station when the station detects a change in the coast station identity after the cr

31、iteria given in CCIR Recommendation 587. A.2 Each MSC is connected to a location register which keeps an updated list of the current location of ail ship stations registered in that MSC (the home MSC of the stations). The home MSC of a ship station should be uniquely determined from the MID and poss

32、ibly one or two additional digits of the ship station number. The location registers are interconnected for mutual updating of the location of ship stations. A.3 Insofar as routing of telex calls to ships is concerned, there are several possibilities: A.3.1 The telex call is always routed directly t

33、o the home MSC by the procedures given in 3.3.3 i). If the called ship is at another MSC (a visited MSC) than the home MSC, the call is rerouted by the home MSC to the appropriate destination. A.3.2 in 3.3.3 ii). The further routing of the call may then be done by either of the following methods: Th

34、e call is routed to an MSC or location register in the calling subscribers country by the method given i) the call is routed to the home MSC and, if required, rerouted by that MSC as described in A.3.1 above; ii) the MSC in the country of origin interrogates the home location register of the mobile station in order to obtain the required routing information. If the called ship station is located in some visited MSC, the MSC may then route the call directly to the required destination. Recommendation U.62 (03/93) 5