1、National Standard of CanadaCAN/CSA-ISO/IEC 8480-01(ISO/IEC 8480:1995)International Standard ISO/IEC 8480:1995 (second edition, 1995-09-15), has been adopted withoutmodification as CSA Standard CAN/CSA-ISO/IEC 8480-01, which has been approved as a NationalStandard of Canada by the Standards Council o
2、f Canada.ISBN 1-55324-410-9 March 2001Reference numberISO/IEC 8480: 1995(E)The Canadian Standards Association, which The Standards Council of Canada is theoperates under the name CSA International coordinating body of the National Standards system, (CSA), under whose auspices this National Standard
3、has a federation of independent, autonomousbeen produced, was chartered in 1919 and accredited by organizations working towards the furtherthe Standards Council of Canada to the National development and improvement of voluntaryStandards system in 1973. It is a not-for-profit, standardization in the
4、national interest.nonstatutory, voluntary membership association The principal objects of the Council are to foster engaged in standards development and certification and promote voluntary standardization as a means activities. of advancing the national economy, benefiting theCSA standards reflect a
5、 national consensus of producers health, safety, and welfare of the public, assisting and users including manufacturers, consumers, and protecting the consumer, facilitating domestic retailers, unions and professional organizations, and and international trade, and furthering internationalgovernment
6、al agencies. The standards are used widely cooperation in the field of standards.by industry and commerce and often adopted by A National Standard of Canada is a standard whichmunicipal, provincial, and federal governments in their has been approved by the Standards Council ofregulations, particular
7、ly in the fields of health, safety, Canada and one which reflects a reasonablebuilding and construction, and the environment. agreement among the views of a number of capableIndividuals, companies, and associations across Canada individuals whose collective interests provide to theindicate their sup
8、port for CSAs standards development greatest practicable extent a balance ofby volunteering their time and skills to CSA Committee representation of producers, users, consumers, andwork and supporting the Associations objectives others with relevant interests, as may be appropriatethrough sustaining
9、 memberships. The more than 7000 to the subject in hand. It normally is a standardcommittee volunteers and the 2000 sustaining which is capable of making a significant and timelymemberships together form CSAs total membership contribution to the national interest.from which its Directors are chosen.
10、 Sustaining Approval of a standard as a National Standard ofmemberships represent a major source of income for Canada indicates that a standard conforms to theCSAs standards development activities. criteria and procedures established by the StandardsThe Association offers certification and testing s
11、ervices Council of Canada. Approval does not refer to thein support of and as an extension to its standards technical content of the standard; this remains thedevelopment activities. To ensure the integrity of its continuing responsibility of the accreditedcertification process, the Association regu
12、larly and standards-development organization.continually audits and inspects products that bear the Those who have a need to apply standards areCSA Mark. encouraged to use National Standards of CanadaIn addition to its head office and laboratory complex in whenever practicable. These standards are s
13、ubject Toronto, CSA has regional branch offices in major centres to periodic review; therefore, users are cautioned across Canada and inspection and testing agencies in to obtain the latest edition from the organizationeight countries. Since 1919, the Association has preparing the standard.developed
14、 the necessary expertise to meet its corporate The responsibility for approving National Standards mission: CSA is an independent service organization of Canada rests with thewhose mission is to provide an open and effective forum Standards Council of Canadafor activities facilitating the exchange o
15、f goods and 270 Albert Street, Suite 200services through the use of standards, certification and Ottawa, Ontario, K1P 6N7related services to meet national and international needs. CanadaFor further information on CSA services, write toCSA International178 Rexdale BoulevardToronto, Ontario, M9W 1R3Ca
16、nadaAlthough the intended primary application of this Standard is stated in its Scope, it is importantto note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Canadian Standards AssociationInformation technology Telecommun
17、ications and informationexchange between systems DTE/DCE interface back-up controlCAN/CSA-ISO/IEC 8480-01 operation using ITU-T Recommendation V.24 interchange circuitsMarch 2001 CSA/1CAN/CSA-ISO/IEC 8480-01Information technology Telecommunications andinformation exchange betweensystems DTE/DCE inte
18、rface back-up control operation using ITU-TRecommendation V.24 interchangecircuitsCSA PrefaceStandards development within the Information Technology sector is harmonized with internationalstandards development. Through the CSA Technical Committee on Information Technology (TCIT),Canadians serve as t
19、he Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 onInformation Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO memberbody for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of theInternational Telecommunicat
20、ion Union (ITU), Canada participates in the International Telegraph andTelephone Consultative Committee (ITU-T).This International Standard was reviewed by the CSA TCIT under the jurisdiction of the StrategicSteering Committee on Information Technology and deemed acceptable for use in Canada. (Acomm
21、ittee membership list is available on request from the CSA Project Manager.) From time to time,ISO/IEC may publish addenda, corrigenda, etc. The CSA TCIT will review these documents for approvaland publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update orconta
22、ct a CSA Sales representative. This Standard has been formally approved, without modification, bythese Committees and has been approved as a National Standard of Canada by the Standards Council ofCanada.March 2001 CSA International 2001All rights reserved. No part of this publication may be reproduc
23、ed in any form whatsoever without the prior permission ofthe publisher. ISO/IEC material is reprinted with permission. Inquiries regarding this National Standard of Canada shouldbe addressed to CSA International, 178 Rexdale Boulevard, Toronto, Ontario, M9W 1R3.INTERNATIONAL STANDARD 8480 Second edi
24、tion 1995-09-I 5 Information technology - Telecommunications and information exchange between systems - DTE/DCE interface back-up control operation using ITU-T Recommendation V.24 interchange circuits Technologies de Iinforma tion - T6lGcommunica tions et 6change dinformation entre systgmes - Dispos
25、itif de secours a la jonction ETTD/ETCD r6alis6 ;i Iaide des circuits dkhange de la Recommandation UT-T V.24 Reference number ISO/I EC 8480: 1995(E) ISO/IEC 8480: 1995(E) Foreword lS0 (the International Organization for Standardization) and IEC (the Inter- national Electrotechnical Commission) form
26、the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. IS0 and IEC tec
27、hnical commit- tees collaborate in fields of mutual interest. Other international organiza- tions, governmental and non-governmental, in liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC have established a joint technical committee, lSO/IEC JTC
28、 1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for vot- ing. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard lSO/IEC 8480 was prepared by Joint Tech
29、nical Committee lSO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecommunications and information exchange between systems. This second edition cancels and replaces the first edition (IS0 8480:1987), which has been technically revised. 0 lSO/lEC 1995 All rights reserved. Unless otherwise
30、specified, 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 from the publisher. I SO/I EC Copyright Off ice l Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed
31、in Switzerland ii ISOllEC 8480 : 1995 (E) Introduction Where data transmission is provided on a leased line, there may be a requirement to provide back-up operation, to be brought into use whenever transmission via the leased line is, for any reason, not possible. There are several possible back-up
32、facilities: - back-up of a 2-wire leased line by one GSTN line; - back-up of a 4-wire leased line by one GSTN line; - back-up of a 4-wire leased line by two GSTN lines; - back-up of a 2-wire/4=wire leased line by one/two lines of a private switched network; - back-up of a 2-wire leased adaptor ; - b
33、ack-up of a 4-wire leased 1 - ine by one ine by one SDN SDN line, using a terminal line, using a terminal adaptor . NOTES I - This list may not be exhaustive. 2 - the terminal adaptor may be separate equipment or physically combined with the DCE. The variety of facilities should not be visible in th
34、e protocol used at the DTElDCE interface to exchange the interface control and status information necessary for back-up control. To achieve this, a standardised approach to the required protocol is essential. The majority of applications are, however, restricted to the first two of the listed possib
35、ilities. In consequence, this international Standard describes the protocol requirements where only one back-up facility is provided as the alternative to data transmission on the leased line. For other arrangements of facilities, although this International Standard is not directly applicable, it n
36、evertheless should be used as a guide to the protocol requirements. Terminal Adaptor functions are described in ITU-T Recommendation (previously CCITT Recommendation) V. II 0, Support of data term!& equipments wifh V-series type interfaces by an integrated services digital network, and CCITT Recomme
37、ndation V. 120, Supporf by an /SD/V of data terminal equipment with V-series type interfaces with provision for statistical muhpexing. . . . III This page intentionally left blank INTERNATIONAL STANDARD 0 ISCMEC MMEC 8480 : 1995 (E) Information technology - Telecommunications and information exchang
38、e between systems - DTE/DCE interface back-up control operation using IT&T Recommendation V.24 interchange circuits 1 scope This international Standard specifies the procedures for back-up operation applicable to data transmission on a leased line when implemented through a single interface, control
39、ling both the leased and the back-up facilities, using KU-T Recommendation V.24 interchange circuits in conjunction with either the 25- pole connector (IS0 2110) or the 26.pole connector (ISOIIEC 11569). The method used to switch the transmission of data automatically from the leased line to or from
40、 the back-up facility is not specified in this International Standard. This International Standard is not applicable where back-up (calling or answering) is achieved by manual means. NOTES 1 The procedures specified in this International Standard may be used at the answering end only, the calling en
41、d only, or both ends of a connection. 2 An ordinary DCE (i.e. one not implementing back-up control) may be provided at either end of the back-up circuit and only for back-up purposes. For example, a calling station could provide one or more separate auto-dial GSTN lines to provide back-up on demand
42、to a greater number of leased lines. 2 Normative references The following standards contain provisions which, through reference in this text? constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, an
43、d parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 21 IO:1 989, lnformafion technol
44、ogy - Data communication - 25-pole DTWDCE interface connector and confact number assignments. ISO/IEC 11569:1993, information technology - Telecommunications and information exchange between systems - 26-pole interface connector mateabilify dimensions and confacf number assignments. ITU-T Recommenda
45、tion V.24: 1993, List of definifions for interchange circuits between data terminal equipment and data circuit-terminating equipment. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 answering station: the station at which the DCE switches to the ba
46、ck-up facility when a back-up request is received (e.g. an incoming call). 3.2 authorized mode: the mode in which switching to the back-up facility is done at the DCE initiative when the DCE is authorized by the DTE to do so. NOTE - In the event that the DTE cannot control this facility over the int
47、erface, selection of this mode within the DCE during installation is permitted. 3.3 calling station: the station at which the DCE has to send to the called station a back-up request (e.g. a call for the other end to switch to the back-up facility). 3.4 direct mode: the mode in which switching to the
48、 back-up facility is done at the DTE initiative. 4 Switching to back-up operation The state diagrams applicable to back-up operation, encompassing the procedures at both the calling and the answering stations, are shown in figure 1 for direct mode, and in figure 2 for authorized mode. When interchan
49、ge circuit 108 is implemented, it shall be in the ON condition. When circuit 108 is not implemented, the DCE shall operate as if circuit 108 were present and in the ON condition. 1 Previously CCITT Recommendation 1 ISOllEC 8480 : 1995 (E) 0 ISCMEC 4.1 Answering station 4.1.1 Direct mode In this mode, after receiving an incoming call, the DTE turns ON circuit 116/l at the time that it wants to force the DCE to switch to the back-up facility. Operation: The DCE, which is connected to the leased line, when it receives a call on the back-up line, turns ON circuit 125. T
