1、STD-ITU-T RECMN F-LZ7-ENGL 177b = 48b2.571 0632206 10b INTERNATIONAL TELECOMMUNICATION UN ION ITU=T TELECOMM U N I CATI ON STANDARDIZATION SECTOR OF ITU FA27 (I 0/96) SERIES F: NON-TELEPHONE TELECOMMUNICATION SERVI CES Mobile service - Mobile services and multidestination satellite services Operatio
2、nal procedures for interworking between the international telex service and the service offered by the INMARSAT-C system ITU-T Recommendation F. 127 (Previously CCITT Recommendation) STD-ITU-T RECMN F.127-ENGL 179b I 48b257L Ob32207 O42 M ITU-T F-SERIES RECOMMENDATIONS NON-TELEPHONE TELECOMMUNICATIO
3、N SERVICES TELEGRAPH SERVICE Operating methods for the international public telegram service The gentex network Message switching The international telemessage service The international telex service Statistics and publications on international telegraph services Scheduled and leased communication s
4、ervices Phototelegraph service MOBILE SERVICE F. 1-F.109 F. 1 -F. 19 F.20-F .29 F.30-F.39 F.40-F.58 F.59-F.89 F.90-F.99 F. 100-F. lo4 F. 105-F.109 F.110-F.159 Mobile services and muitidestination satellite services F. 110-F. 159 TELEMATIC SERVICES Public facsimile service Teletex service Videotex se
5、rvice General provisions for telematic services MESSAGE HANDLING SERVICES DIRECTORY SERVICES DOCUMENT COMMUNICATION Document communication Programming communication interfaces DATA TRANSMISSION SERVICES AUDIOVISUAL SERVICES ISDN SERVICES LJNIVERSAL PERSONAL TELECOMMUNICATION HUMAN FACTORS F.160-F.39
6、9 F.160-F.199 F.200-F.299 F.300-F.349 F.350-F.399 F.400-F.499 F.500-F.549 F.550-F.599 F.550-F.579 F.580-F.599 F.600-F.699 F.700-F.799 F.800-F 349 F.850-F.899 F.900-F.999 For further details, please refer to ITU-T List of Recommendations. STDOITU-T RECMN FmL27-ENGL 199b E iBb2.571 0b32208 TB9 - FOREW
7、ORD The IT-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them with a view to standardizing telecommunications on a
8、worldwide basis. The World Telecommunication Standardization Conference (WSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covere
9、d by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). IT-T Recommendation F.127 was revised by ITU-T Study Group 1 (1993-1996) and was approved by the WSC (Geneva, 9-18 October 1996). NOTE In this Recommendation, the expression “Administration” is used for conciseness t
10、o indicate both a telecommunication administration and a recognized operating agency. O ITU 1997 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 microfilm, without permission in writing f
11、rom the ITU. STD-ITU-T RECMN F.127-ENGL 177b m 48b2591 Ub32207 715 m CONTENTS 1 Definitions 2 Scope 3 Introduction 4 Principles of operation . 5 Operational procedures International telex service to INMARSAT-C system . Calls from an MES to subscribers of the international telex service MES-to-MES ca
12、lls utilizing the international telex service 5.1 5.2 5.3 Annex A . Alphabetical list of abbreviations used in this Recommendation . Page 1 1 2 2 2 2 4 4 4 STD-ITU-T RECMN F.127-ENGL 199b M 4b259L Ob32210 b37 = Recommendation F.127 OPERATIONAL PROCEDURES FOR INTERWORKING BETWEEN THE INTERNATIONAL TE
13、LEX SERVICE AND THE SERVICE OFFERED BY THE INMARSAT-C SYSTEM (revised 1992 and 1996) The ITU-T, considering a) INMARSAT-C systems; that INMARSAT has introduced various mobile services based on the INMARSAT-A, Mh4ARSAT-B and b) that Recommendation F. 120 specifies ship station identification for the
14、maritime mobile-satellite service; c) INMARSAT; that Recommendation F.125 specifies the numbering plan for the maritime mobile-satellite service of d) INMARSAT-C system, that the provision of interworking with the international telex service is a standard requirement within the unanimous2y recommend
15、s that operational procedures of intenvorking between the international telex service and the service provided by the INMARSAT-C system be in accordance with this Recommendation. 1 Definitions This Recommendation defines the following terms: 1.1 purpose of this Recommendation, the terms “ship earth
16、station” and “mobile earth station” are interchangeable. ship earth station is defined in Article 1, section 4.16 of the Radio ReguZations, ITU Geneva, 1982. For the 1.2 purpose of this Recommendation, the terms “coast earth station” and “land earth station” are interchangeable. coast earth station
17、is defined in Article 1, section 4.14 of the Radio Regulations, IT Geneva, 1982. For the 1.3 transmission system and the international telex service. The mobile satellite store-and-forward unit is the functional interface between the mobile satellite message 2 Scope 2.1 The purpose of this Recommend
18、ation is: a) to standardize procedures for the subscribers of the international telex service calling Mobile Earth Stations (MESS) in the INMARSAT-C system; b) c) to standardize procedures for an MES calling subscribers of the international telex service; to standardize procedures for MES-to-MES cal
19、ls that transit the international telex network. STD-ITU-T RECMN F.327-ENGL 399b D 4862573 Ob322L3 573 M 3 Introduction 3.1 store-and-forward operation is supported when interworking with the intemational telex service. The characteristics of the mobile satellite circuit provided by the INMARSAT-C s
20、ystem are such that only 3.2 ment No. 3 to the F-Series Recommendations (Blue Book, Fascicle 11.4, Melbourne, 1988). 3.3 In the interests of ensuring that the optimum use is made of the international telex service, Administrations may wish to advise their customers of any differences in messaging pr
21、ocedures between the service offered by the INMARSAT-C system and normal telex procedures as offered by other INMARSAT standard systems. 3.4 to existing implementations of Mobile Satellite Store-and-Forward Unit (MSSFU). A general description of the INMARSAT-C system and the services it may support
22、is given in Supple- The provisions of this Recommendation should be applied to future implementation and, as far as practicable, 4 Principles of operation 4.1 basis. Thus, conversational mode interworking between terminals is not provided. Communication between subscribers of the international telex
23、 service and an MES is on a store-and-forward 4.2 Interworking between the international telex service and the INMARSAT-C system may employ either one- stage or two-stage selection procedures for the delivery of telex messages to an MES. Administrations may provide either or both modes of operation.
24、 These services may be extended across international boundaries on a bilateral basis. Where no such bilateral agreement exists, the Administration operating the MSSFU may clear the call and return the service signal (NA). 4.3 In mobile to fixed direction, subscribers to the mobile-satellite service
25、provided by the INMARSAT-C system may send single messages to the subscribers of the international telex service and to the appropriate applications. The messages are forwarded by the MSSFU via the international telex service. 4.4 For calls from MES-to-MES, the procedures for handling calls between
26、different satellite regions is not the subject for intemational standardization. Such calls which utilize the intemational telex service should follow normal telex procedures. 5 Operational procedures 5.1 International telex service to INMARSAT-C system 5.1.1 5.1.1.1 procedures. One-stage selection
27、by the telex customer A customer of the international telex service may place a call to a mobile earth station using normal telex 5.1.1.2 information, plus any necessary prefix and end-of-selection signal: The originating telex subscriber, when calling an INMARSAT-C MES, should input the following s
28、election 58S4X1 X8 where 58s is the telex destination code in accordance with Recommendation F.69 (S = 1, 2, 3 or 4), 4 is the T-digit in accordance with Recommendation F.125, and XI X8 are part of the MES identity in accordance with Recommen- dation F.125. 5.1.1.3 On receipt of this address, the MS
29、SFU should check that the addressed MES is logged into the satellite region and should, if the result is positive, return the call connect signal in accordance with the relevant U-Series Recom- mendations. If the check fails, the call attempt should be cleared by the MSSFU with the appropriate servi
30、ce signal in accordance with Recommendation F. 13 1. 5.1.1.4 The MSSFU should return the MES answerback, formatted in accordance with Recommendation F.74. 5.1.1.5 of the originating telex subscriber. The MSSFU should transmit a WRU signal following the MES answerback in order to capture the answerba
31、ck STD-ITU-T RECMN F-127-ENGL L77b LiBb2.571 Ob32212 40T 5.1.1.5 bis Where the call to the MSSFU is being handled by a telex SFU operating in accordance with Recommen- dations F.72 and U.81 on behalf of a customer of the intemational telex service, the telex SFU identification should be forwarded to
32、 the MSSFU immediately following receipt of the called MES answerback. This should comprise the code expression CI, the characters SFU and the TNIC of the parent network of the telex SFU. This will then allow the procedures which subsequently follow to be under the fll control of the telex SFU with
33、no prompt signals returned by the MSSFU. Where the call to the MSSFU is originated by a subscriber of the intemational telex service operating in interactive or manual mode, the procedures of 5.1.1.6 to 5.1.1.8 should be applied. 5.1.1.6 described in Recommendation U.74. The calling telex address sh
34、all be determined from the received telex answerback in accordance with the rules Where the calling telex address cannot be determined, the MSSFU should wait 3 seconds fiom the end of the received answerback to enable the originating telex customer to voluntarily input his telex address, in accordan
35、ce with Recommendation U.208. At the end of this period, the MSSFU shall return the prompt signal ADD. If the calling telex address is not received within 15 seconds of the ADD prompt, another ADD prompt signal shall be returned. If another 15 seconds elapse without the receipt of the calling telex
36、address, the connection shall be cleared by the MSSFU. Optionally, the call may be accepted by the MSSFU, and the GA prompt returned, where, in the event of non-delivery of an accepted message, alternative arrangements are in place to provide a non-delivery notification message to the originating te
37、lex subscriber, for example, spill out to an assistance position. It should be noted that some MSSFU do not support the ADD procedure. In this case, the MSSFU should return the code expression REJ and clear the call. 5.1.1.7 Input of the message may now be commenced by the originating telex customer
38、. 5.1.1.8 The preferred method of clearing to be applied by the originating telex customer is by the use of the End-of-Transmission (EOT) signal, four times combination 26 in figures case (+i-+) which need not be passed to the intended recipient. This method enables the provision of a message refere
39、nce number by the MSSFU which could be useful to the message onginator should a Non-Delivery Notification (NDN) be subsequently received. However, it should be recognized that the originating telex customer could clear the connection in one of the following ways: a) The customer may close his messag
40、e with the End-of-Message (EOM) signal N“N which is followed by a period of idle condition of 30 seconds. This should be interpreted by the MSSFU as being equivalent to an EOT signal and return the input transaction accepted for delivery (ITD) sequence as specified in Recommendation U.208. b) The cu
41、stomer may close his message with the end-of-message signal “NN followed immediately by a clear, having optionally exchanged answerbacks, in which case the MSSFU should proceed as in c). The call may be cleared without EOT or EOM, in which case all text received should be forwarded to the MES in the
42、 normal way, optionally including a statement which would advise the recipient that the message originator did not clear the connection using the EOT procedure and that consequently the message may be incomplete. To facilitate clearing by Telex Automatic Emitting Device (TAED) which may interpret a
43、clear initiated by the MSSFU as an abnormal condition, the ITD sequence should be followed by a period of idle condition to enable clearing by TAEDs in accordance with Recommendation S.20. c) d) 5.1.1.9 address MES should commence at the earliest opportunity. Following clearing of the connection acr
44、oss the international telex network, delivery of the message to the 5.1.1.10 The message should not be held in the MSSFU for more than 24 hours. 5.1.1.11 In the event of non-delivery of the message to the MES, it is the responsibility of the MSSFU to return an NDN directly to the originating telex c
45、ustomer in accordance with Recommendation U.208. 5.1.1.12 If message delivery has not commenced at the expiry of the 24-hour period, an NDN should be provided to the originating telex customer. However, any delivery procedure which has already been commenced by the MSSFU that would exceed the 24-hou
46、r period, should be completed. STD-ITU-T RECMN FmL27-ENGL 199b I48b259L Ob32213 34b W 5.1.2 Two-stage selection 5.1.2.1 Subscribers of the intemational telex service should use normal telex call establishment procedures to access the MSSFU, which is allocated a national number for this purpose, the
47、general service principles and access procedures and protocols being in accordance with Recommendations F.72 and U.80 for two-stage access to a store-and-forward unit. 5.1.2.2 The MSSFU should accept both single and multi-addressed calls, the address line containing an optional attention information
48、 field in accordance with Recommendation F.72 to indicate the expected answerback of the recipient, attention information, class of delivery indicator, and a request for positive delivery notification. The list of addresses, either single or multiple, should be closed by the End-of-Address (EOA) sig
49、nal BT. As a minimum, the address line should contain the selection information in accordance with 5.1.1.2. 5.1.2.3 delivering a non-delivery advice, the call should be cleared. The call may be accepted where, in the event of non-delivery of a message, alternative arrangements for delivery are provided. The alternative arrangements, for example, may be the provision of an operator position. 5.1.2.4 with Recommendations F.72 and U.80. If the calling address cannot be determined from the calling subscribers answerback for the purpose of The action to be taken when abno
