1、CCITT RECMN*F.BO 91 48b2591 0561087 7 H UNION F.80 CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONS U LTATi VE COM M i TTE E TELEGRAPH AND MOBILE SERVICES OPERATIONS AND QUALITY OF SERVICE BASIC REQUIREMENTS FOR INTERWORKING RELATIONS BETWEEN THE INTERNATIONAL TELEX SERVICE AND OTHER SERVICES Re
2、commendation F.80 L CCITT RECMN*F*BO 91 4862593 05bLO88 7 i NTERNATIONAL TELECOMMU N KATION UN ION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE F.80 TELEGRAPH AND MOBILE SERVICES OPERATIONS AND QUALITY OF SERVICE BASIC REQUIREMENTS FOR INTERWORKING RELATIONS BETWEEN THE INT
3、ERNATIONAL TELEX SERVICE AND OTHER SERVICES Recommendation F.80 Geneva, 1991 CCITT RECMN*F.BO 93 4862591 0563089 O = FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union 0. CCITT is responsible for stu
4、dying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Gr
5、oups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCIT Resolution No. 2 (Melbourne, 1988). Recommendation F.80 was prepared by Study Group I and was approved under the Resolution No. 2 procedure on the 1 lth of October 1
6、991. 1) In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency. 2) A list of abbreviations used in this Recommendation can be found in Annex A. O IT 1991 All rights reserved. No par
7、t 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 from the ITU. CCITT RECVN*F.BO 71 q862.591 05bL090 7 Recommendation F.80 BASIC REQUIREMENTS FOR INTERWORKING RELATIONS BETWEE
8、N THE INTERNATIONAL TELEX SERVICE AND OTHER SERVICES 1 Scope This Recommendation defines the basic requirements which should be observed when defining interworking relations between the international telex service and other services. The aim of this Recommendation is to ensure that by implementing s
9、uch interworking relations no negative influences arise for subscribers of the international telex service. Only the perspective of a telex subscriber communicating with terminais of another service via an interworking function OWF) is considered in this Recommendation. 2 Introduction Providers of n
10、ew and evolving non-voice services are aiming to offer communication relations with the international telex service by introducing interworking functions. The provision of such interworking functions must not reduce the perceived Quality of Service or modiSl the operational procedures of the interna
11、tional telex service. Therefore, when defining interworking functions, the general characteristics of the international telex service, as well as its operational provisions, listed in Recommendations F.59 and F.60, must be considered. Since the specific interworking procedures are defined in detail
12、within numerous Recommendations, it seems beneficial to summarize the basic requirements for interworking relations between the international telex service and other services within one single Recommendation. 3 Interworking principies 3 .O General The conformance of interworking relations to the int
13、ernational telex service is shown in Table 1E.80. Recommendation F.80 1 CCITT RECMN*F.BO 73 4862593 0563073 9 2 Recommendation F.80 CCITT RECMN*F=BU 91 m YB6259L 0563072 O 3.1 One-stage selection In the case of one-stage selection, where the destination terminal will have been assigned a telex numbe
14、r that is part of the national telex numbering plan of the destinaton country, the originating telex subscriber may assume, notwithstanding a received answerback conforming to Recommendation F.74, that a normal telex connection has been established and ali telex characteristics (as listed in Recomme
15、ndation F.59) will be available at the destination terminal. 3.2 Two-stage selection 3.2.1 in the case of a two-stage selection it can generally be assumed that a telex subscriber establishes by intention an interworking relationship with the subscriber of another service. However, it should be reco
16、gnized that a subscriber of the international telex service may not be aware of any or ali of the service parameters of the destination service, in particular of its presentation facilities. 3.2.2 In two-stage-interworking functions 0 the two-stage selection procedure ifseif is already a definite de
17、viation from the normal operational procedures for the originating telex subscriber. Since there is a need to inform the telex subscribers about the details of the selection procedure, it is also feasible to draw the attention of the telex subscribers to the fact, that he or she cannot expect all th
18、e basic characteristics of the international telex service (as listed in Recommendation F.59) to be available at the destination terminal. This limitation must be recognized and telex customers should be recommended to inform themselves about the characteristics of the destination service. 3.3 As it
19、 may not be possible to identdy the service of origin by oniy evaluating the text part of a received message, the operator of the receiving telex terminal should be provided with information to identify the origin of a received message. Therefore it is recommended that an IWF provide the recipient w
20、ith sufficient information on how to recall the originator, for example, a recall address. 3.4 In the particular case of a two-stage IWF/CF (conversion facility) on the telex side, it is recommended that the IWF attach a herald to the text of the message to indicate the source of the message and the
21、 recall address. Such a herald should include two fields, as follows: - the recall address, preceded by the text “FOR RECLL (service address)”; - the IWF/F answerback. 3.5 If, in an interworking relationship, a sender wants the recipient to receive the transmitted message in identical format, he or
22、she should if possible, structure his message according to the presentation facilities of the receiver. 3.6 provider should offer sufficient information on the characteristics of the services concerned. In order to offer a satisfactory usability of service interworking relations to the subscriber, t
23、he service 3.7 These operational instructions for the subscriber should include indications on any deviations from the general characteristics of the international telex service, as listed in Recommendation F.59, inherent to the interworking function. 3.8 should be indicated to the user. In order to
24、 keep interworking relations as transparent as possible, any concatenation of interworking relations 3.9 In order to provide the originating telex subscriber with the ability to determine the status of a message previously deposited, or to cancel such a message, the IWF should provide, where relevant, a status enquiry function. This should be implemented in accordance with Recommendations F.89 and U.220. Recommendation F.80 3
