1、 Recommendation ITU-R M.625-4(03/2012)Direct-printing telegraph equipment employing automatic identificationin the maritime mobile serviceM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rec. ITU-R M.625-4 Foreword The role of the Radiocommunication Sector is to ensure the
2、 rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Ra
3、diocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex
4、 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent in
5、formation database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (televis
6、ion) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed servi
7、ce systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2012 ITU 2012
8、All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R M.625-4 1 RECOMMENDATION ITU-R M.625-4*Direct-printing telegraph equipment employing automatic identification in the maritime mobile service (1986-1990-1992-1995
9、-2012) Scope The Recommendation provides in Annex 1 characteristics of direct-printing telegraph equipment employing a 7-unit ARQ method for selective communication, a 7-unit FEC method for broadcast mode and automatic identification. Equipment developed in accordance with this Recommendation provid
10、es compatibility with equipment without maritime mobile service identity (MMSI) conforming to Recommendation ITU-R M.476. The ITU Radiocommunication Assembly, considering a) that ship stations or ship stations and coast stations, equipped with start-stop apparatus employing the ITU-T International T
11、elegraph Alphabet No. 2, are interconnected by means of radio circuits; b) that direct-printing telegraph equipment in the maritime mobile service is used for communication: between a ship station and a subscriber of the (international) telex network; between a ship station and a coast station or be
12、tween two ship stations; between a ship station and an extended station (ship owner) via a coast station; in a broadcast mode from a coast station, or a ship station, to one or more ship stations; c) that direct-printing telegraphy are part of the Global Maritime Distress Safety System; d) that the
13、broadcast mode cannot take advantage of an ARQ method, as a return path is not used; e) that for the broadcast mode a forward error-correcting (FEC) method should be used; f) that the period for synchronization and phasing should be as short as possible; g) that most of the ship stations do not read
14、ily permit the simultaneous use of radio transmitter and receiver; h) that a direct-printing telegraph system employing error-detecting and error-correcting methods in accordance with Recommendation ITU-R M.476, is in actual operation; *This Recommendation should be brought to the attention of the I
15、nternational Maritime Organization (IMO) and the Telecommunication Standardization Sector (ITU-T). 2 Rec. ITU-R M.625-4 j) that the use of direct-printing telegraph equipment benefits by an unambiguous identification of both stations when a circuit is established or re-established; k) that unambiguo
16、us identification can be accomplished by the exchange of self-identification signals between the ARQ equipments at the 7-unit level; l) that Recommendation ITU-R M.585 and ITU-T Recommendations E.210 and F.120 provide information assigning MMSIs; m) that, in the interest of having a unique identity
17、assigned to each ship station for distress and safety and other telecommunication purposes, the address capability should allow the use of MMSIs in accordance with the provisions of Recommendation ITU-R M.585; n) that equipment built in accordance with Recommendation ITU-R M.476 cannot provide for t
18、he use of MMSIs mentioned in l); o) that there is a need to provide for compatibility to the extent possible with equipments built in accordance with Recommendation ITU-R M.476; however, unambiguous identification of both stations cannot be achieved when circuits are established with equipments buil
19、t in accordance with Recommendation ITU-R M.476, recommends 1 that for direct-printing telegraph circuits in the maritime mobile service, a 7-unit ARQ method should be employed; 2 that for the direct-printing telegraph service in the broadcast mode, a 7-unit forward acting error-correcting method, u
20、sing time diversity, should be employed; 3 that equipment designed in accordance with 1 and 2 should employ automatic identification and have the characteristics given in Annex 1. Rec. ITU-R M.625-4 3 Annex 1 TABLE OF CONTENTS Page 1 General (mode A (ARQ) and mode B (FEC) 5 2 Conversion tables . 6 2
21、.1 General . 6 2.2 Traffic information signals . 6 2.3 Service information signals 6 2.4 Identification and check-sum numbers and signals 8 2.5 Check-sum signal derivation 8 3 Characteristics, mode A (ARQ) . 9 3.1 General 9 3.2 Master and slave arrangements . 9 3.3 The information sending station (I
22、SS) 9 3.4 The information receiving station (IRS) . 10 3.5 Phasing procedure . 10 3.6 Automatic identification . 11 3.7 Traffic flow . 13 3.8 Rephasing procedure 15 3.9 Summary of service blocks and service information signals 17 4 Characteristics, mode B (FEC) . 17 4.1 General 17 4.2 The sending st
23、ation (CBSS and SBSS) 18 4.3 The receiving station (CBRS and SBRS) . 18 4.4 Phasing procedure . 18 4.5 Selecting calling procedure (selective B-mode) . 18 4.6 Traffic flow . 19 Appendix 1 SDL diagrams (mode A) . 29 Appendix 2 Phasing procedure with automatic identification in the case of a 7-signal
24、call identity (calling station) 33 4 Rec. ITU-R M.625-4 Page Appendix 3 Rephasing procedure with automatic identification in the case of a 7-signal call identity (calling station) 36 Appendix 4 Phasing procedure without automatic identification in the case of a 4-signal call identity (calling statio
25、n) . 39 Appendix 5 Rephasing procedure without automatic identification in the case of a 4-signal call identity (calling station) . 40 Appendix 6 Phasing procedure with automatic identification in the case of a 7-signal call identity (called station) 41 Appendix 7 Rephasing procedure with automatic
26、identification in the case of a 7-signal call identity (called station) 44 Appendix 8 Phasing procedure without automatic identification in the case of a 4-signal call identity (called station) 47 Appendix 9 Rephasing procedure without automatic identification in the case of a 4-signal call identity
27、 (called station) 48 Appendix 10 Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the ISS position) 49 Appendix 11 Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the IRS po
28、sition) 52 Appendix 12 State overview diagrams 54 Sheet 1 Phasing procedure with automatic identification in the case of a 7-signal call identity (calling station) and traffic flow if the station is in the ISS position . 54 Sheet 2 Rephasing procedure with automatic identification in the case of a 7
29、-signal call identity (calling station) and traffic flow if the station is in the ISS position . 55 Sheet 3 Phasing procedure without automatic identification in the case of a 4-signal call identity (calling station) and traffic flow if the station is in the ISS position . 56 Sheet 4 Rephasing proce
30、dure without automatic identification in the case of a 4-signal call identity (calling station) and traffic flow if the station is in the ISS position . 57 Sheet 5 Phasing procedure with automatic identification in the case of a 7-signal call identity (called station) and traffic flow if the station
31、 is in the IRS position 58 Sheet 6 Rephasing procedure with automatic identification in the case of a 7-signal call identity (called station) and traffic flow if the station is in the IRS position 59 Sheet 7 Phasing procedure without automatic identification in the case of a 4-signal call identity (
32、called station) and traffic flow if the station is in the IRS position 60 Sheet 8 Rephasing procedure without automatic identification in the case of a 4-signal call identity (called station) and traffic flow if the station is in the IRS position 61 Rec. ITU-R M.625-4 5 1 General (mode A (ARQ) and m
33、ode B (FEC) 1.1 The system in both Mode A (ARQ) and Mode B (FEC) is a single-channel synchronous system using the 7-unit constant ratio error-detecting code as listed in 2.2 and 2.3. 1.2 FSK modulation is used on the radio link at 100 Bd. The equipment clock controlling the modulation rate should ha
34、ve an accuracy of 30 parts in 106or better. 1.3 The class of emission is F1B or J2B with a frequency shift on the radio link of 170 Hz. When frequency shift is effected by applying audio signals to the input of a single-sideband transmitter, the centre frequency of the audio spectrum applied to the
35、transmitter should be 1 700 Hz. 1.4 The radio-frequency tolerance of the transmitter and the receiver should be in accordance with Recommendation ITU-R SM.1137. It is desirable that the receiver employs the minimum practicable bandwidth (see also Report ITU-R M.585). NOTE 1 The receiver 6 dB bandwid
36、th should preferably be between 270 and 340 Hz. 1.5 For direct connection to the international telex network, the line input and output signals should be in accordance with the 5-unit start-stop International Telegraph Alphabet No. 2, at a modulation rate of 50 Bd. 1.6 Equipment designed in accordan
37、ce with this Recommendation is likely to contain high speed digital circuitry. Special care should be taken to avoid interference to other equipment and to minimize susceptibility to interference from other equipment or electrical lines on board ship (see also Recommendation ITU-R M.218). 1.7 When o
38、perating in mode A (ARQ), the called station employs a constant time interval between the end of the received signal and the start of the transmitted signal (tEin Fig. 1). In the case of long propagation distances it is essential to have this tEas short as practicable. However, in the case of short
39、distances it may be desirable to introduce a longer time interval, e.g. 20-40 ms, to accommodate receiver desensitization at the calling station. This time interval can be introduced at the called station either in the ARQ equipment or in the radio equipment. 2 Conversion tables 2.1 General Several
40、kinds of “signals” are used in the system, such as: traffic information signals, service information signals (control signals, idle signals, signal repetition), identification signals, check-sum signals. 2.2 Traffic information signals These signals are used during communication to convey the messag
41、e information which is passed from an information sending station to one or more information receiving stations. Table 1 lists the traffic information signals which may be used. 6 Rec. ITU-R M.625-4 2.3 Service information signals These signals are used to control the procedures taking place over th
42、e radio circuit and do not form part of the transmitted messages. Service information signals are not normally printed or displayed. Table 2 lists the service information signals which may be used. TABLE 1 Combination No. Traffic information signals International Telegraph Alphabet No. 2 Code (1)Tra
43、nsmitted 7-unit signal (2)Letter- case Figure case Bit position (3)1 2 3 4 5 66666 Bit position (3)1 2 3 4 5 6 7 666 11 12 13 14 15 16 17 18 19 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ? : (4)3 (5)(5)(5)8 (Audible signal)( ) . , 9 0 1 4 5
44、 7 = 2 / 6 + ZZAAA ZAAZZ AZZZA ZAAZA ZAAAA ZAZZA AZAZZ AAZAZ AZZAA ZZAZA ZZZZA AZAAZ AAZZZ AAZZA AAAZZ AZZAZ ZZZAZ AZAZA ZAZAA AAAAZ ZZZAA AZZZZ ZZAAZ ZAZZZ ZAZAZ ZAAAZ BBBYYYB YBYYBBB BYBBBYY BBYYBYB YBBYBYB BBYBBYY BYBYBBY BYYBYBB BYBBYYB BBBYBYY YBBBBYY BYBYYBB BYYBBBY BYYBBYB BYYYBBB BYBBYBY YBB
45、BYBY BYBYBYB BBYBYYB YYBYBBB YBBBYYB YYBBBBY BBBYYBY YBYBBBY BBYBYBY BBYYYBB 27 28 29 30 31 32 m m mm (Carriage return) m m mm (Line feed) m m mm (Letter shift) m m mm (Figure shift) mm mm (Space)mm No information AAAZA AZAAA ZZZZZ ZZAZZ AAZAA AAAAA YYYBBBB YYBBYBB YBYBBYB YBBYBBY YYBBBYB YBYBYBB (1
46、)A represents start polarity, Z represents stop polarity (see also Recommendation ITU-R M.490). (2)B represents the higher emitted frequency and Y the lower (see also Recommendation ITU-R M.490). (3)The bit in bit position 1 is transmitted first; B = 0, Y = 1. (4)The pictorial representation shown i
47、s a schematic of which may also be used when equipment allows (ITU-T Recommendation F.1, C9). (5)At present unassigned (see ITU-T Recommendation F.1, C8). Reception of these signals, however, should not initiate a request for repetition. Rec. ITU-R M.625-4 7 TABLE 2 2.4 Identification and check-sum
48、numbers and signals Identification and check-sum numbers and signals are used in the automatic identification procedure in order to provide a means by which, during the establishment or re-establishment of a radio circuit, the stations concerned are clearly and unambiguously identified to each other
49、. The relationship between the transmitted identification signals and their equivalent numbers is shown in Table 3a; Table 3b indicates the conversion from check-sum numbers to the transmitted check-sum signals. TABLE 3a TABLE 3b Mode A (ARQ) Transmitted signal Mode B (FEC) Control signal 1 (CS1) Control signal 2 (CS2) Control signal 3 (CS3) Control signal 4 (CS4) Control signal 5 (CS5) Idle signal Idle signal Signal repetition (RQ) BYBYYBB YBYBYBB BYYBBYB BYBYBBY BYYBYBB BBYYBBY B
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