1、BRITISH STANDARD BS ISO/IEC 9549:1990 Implementation of ISO/IEC 9549:1990 Information technology Galvanic isolation of balanced interchange circuitsBSISO/IEC 9549:1990 This British Standard, having been prepared under the directionof the Information Systems Technology Standards Policy Committee, was
2、 publishedunder the authority ofthe Board of BSI and comes into effect on 28 February 1991 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference IST/6 Draft for comment 89/60073 DC ISBN 0 580 19339 X Committees responsible for this BritishStandard The prep
3、aration of this British Standard was entrusted by the Information Systems Technology Standards Policy Committee (IST/-) to Technical Committee IST/6, upon which the following bodies were represented: Association for Payment Clearing Services British Computer Society British Telecommunications plc Bu
4、siness Equipment and Information Technology Association Department of Trade and Industry (Information Technology Standards Unit) Department of Trade and Industry (National Physical Laboratory) Electricity Supply Industry in England and Wales Electronic Engineering Association HM Treasury (Central Co
5、mputer and Telecommunications Agency) Information Technology Users Standards Association Institute of Data Processing Management Inter-universities Computing Committee Joint Network Team National Computing Centre Ltd. National Health Service OFTEL (Office of Telecommunications) Post Office Telecommu
6、nication Engineering and Manufacturing Association Telecommunications Managers Association Amendments issued since publication Amd. No. Date CommentsBSISO/IEC 9549:1990 BSI 01-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO/IEC 1BSISO/IEC
7、9549:1990 ii BSI 01-2000 National foreword This British Standard reproduces verbatim ISO/IEC 9549:1990 and implements it as the UK national standard. This British Standard is published under the direction of the Information Systems Technology Standards Policy Committee whose Technical Committee IST/
8、6 has the responsibility to: aid enquirers to understand the text present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEIn
9、ternational and European Standards, as well as overseas standards, are available from BSI Sales Department, BSI, Linford Wood, Milton Keynes, MK14 6LE. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their corr
10、ect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO/IEC title page, pages ii to iv, pages 1 to 6 and a back cover. This standard has been u
11、pdated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO/IEC 9549:1990(E) ii BSI 01-2000 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative references 1 3 Symbolic representation of optocoupler comp
12、onents 2 4 Polarities and significant level 3 5 Isolated generator characteristics 3 6 Isolated receiver characteristics 4 7 Fault condition tests 4 8 Interconnection configuration 4 9 Optocoupler component isolation 4 10 Signal distortion 5 11 Environmental constraints 5 Annex A (informative) 6 Fig
13、ure 1 Symbolic representation of isolated generator 2 Figure 2 Symbolic representation of isolated receiver 2 Figure 3 Individual distortion measurement arrangement 5 Figure A.1 Isolated generator interconnection with V.11 receiver 6 Figure A.2 V.11 generator interconnection with isolated receiver 6
14、 Table 1 Receiver differential significant levels 3ISO/IEC 9549:1990(E) BSI 01-2000 iii Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are member
15、s of ISO 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. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organ
16、izations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated
17、 to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 9549 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology. Annex A of this International Standa
18、rd is for information only.iv blankISO/IEC 9549:1990(E) BSI 01-2000 1 Introduction This International Standard specifies a method of galvanically isolating signal exchanges on balanced interchange circuits using optocoupler integrated circuit technology. It may be applied for data transmission in a
19、two-condition code (e.g. NRZ). Galvanic isolation of interchange circuits is required whenever the intercommunicating devices are connected to different mains supplies. In this case, the ground potential difference between the earthing systems frequently is higher than the common mode voltage specif
20、ied for the interchange circuit receiver. Transmission errors and even damage to the receiver may be the result. The optocoupler type of galvanic isolation may also be used when high external signal interferences have to be minimized. This situation may exist with long interchange circuits and opera
21、tion at higher data signalling rates. The specifications of this International Standard are compatible with both ISO 8482 (multipoint connection) and CCITT Recommendation V.11 (point-to-point connection) because of application flexibility and the fact that there is not much difference in the paramet
22、ers for the component design. Bidirectional data transmission is provided and requires the implementation of an isolated generator and an isolated receiver. Their unbalanced interfaces are not specified in order to provide flexibility for implementations and device manufacturers. 1 Scope 1.1 This In
23、ternational Standard specifies galvanic isolation of balanced interchange circuits using optocoupler integrated circuit technology and is provided for data transmission in the two-condition code (e.g. NRZ). The electrical characteristics are compatible with both ISO 8482 and CCITT Recommendation V.1
24、1. NOTECompatible means to allow interoperation with devices having interchange circuits conforming to the electrical characteristics specified in the referenced standards. Annex A shows interoperation with CCITT Recommendation V.11 interchange circuits in a point-to-point environment. 1.2 The speci
25、fications are given in terms of parameters and measurements for an isolated generator and an isolated receiver. These components may be used in twisted pair 2-wire or 4-wire point-to-point connections up to 1 000 m or multipoint connections up to 500 m for speeds up to2Mbit/s for point-to-point conn
26、ections and1Mbit/s for multipoint connections. For data signalling rates up to 20 kbit/s, device manufacturers may optimize their component design. 1.3 Options are provided to meet special application requirements, such as isolated generator high impedance control; isolated receiver circuit failure
27、detection capability; line termination in point-to-point configuration. 1.4 This International Standard does not describe a complete equipment interface in terms of mechanical, electrical and functional/procedural specifications. 2 Normative references The following standards contain provisions whic
28、h, 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, and parties to agreements based on this International Standard are encouraged to investigate the possibility
29、of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 8482:1987, Information processing systems Data communication Twisted pair multipoint interconnections. CCITT Recommendation V.11:1988, Electri
30、cal characteristics for balanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications. ISO/IEC 9549:1990(E) 2 BSI 01-2000 3 Symbolic representation of optocoupler components 3.1 Isolated generator 3.2 Isolated receiver A,B C D,D E
31、F F C G Balanced signal output Zero volt reference interchange point Floating power supply Unbalanced station power supply Unbalanced signal input Unbalanced high impedance control Isolated generator Figure 1 Symbolic representation of isolated generator A,B A,B + B C D,D E F R Balanced signal input
32、 Balanced terminated signal input option Zero volt reference interchange point Floating power supply Unbalanced station power supply Unbalanced signal output Isolated receiver Figure 2 Symbolic representation of isolated receiverISO/IEC 9549:1990(E) BSI 01-2000 3 4 Polarities and significant levels
33、4.1 Balanced signal output/input The generator polarities and receiver differential significant levels correspond to those of subclause 7 of ISO 8482 and clause 4 of CCITT RecommendationV.11. Table 1 Receiver differential significant levels 4.2 Unbalanced signal output/input The generator polarities
34、 and receiver differential significant levels are in accordance with the technology used on the unbalanced interface. 5 Isolated generator characteristics 5.1 Balanced signal output A generator component is measured in the active, low impedance state in accordance with the measurement arrangements i
35、n ISO 8482. The generator component may be supplied for the measurements by an appropriate single-rail power supply for the unbalanced input side and the balanced output side. Alternatively a floating power supply may be used for the balanced output side. The tests are made for either binary state.
36、For these states the symbols used in ISO 8482 are |V| and |, respectively. 5.1.1 Open circuit voltage, V o As in subclause 8.1 of ISO 8482 5.1.2 Terminated output voltage, V t As in subclause 8.3 of ISO 8482 5.1.3 Offset voltage, V os As in subclause 8.2 of ISO 8482 5.1.4 Rise time, t r , and imbala
37、nce voltage, V e As in subclause 8.4 of ISO 8482 5.2 Inactive high impedance state measurements option 5.2.1 Static measurements When in the high impedance state and with test loads of 50 7 connected between each generator output point and point C, the magnitude of the voltage V hmeasured between po
38、ints A and B shall not exceed 4mV whatever the logical condition of the generator input data lead. When the generator is in the high impedance state, with voltages ranging between 6 V and + 6 V applied between each output point and point C, the magnitude of the output leakage currents I xaand I xbsh
39、all not exceed 150 4A. The same situation applies in the power-off condition. 5.2.2 Dynamic measurements During transitions of the generator output between the low impedance state and the high impedance state, the differential signal measured across a 100 7 test load connected between the generator
40、points A and B shall be such that the amplitude changes from 10% to 90% of the steady state voltage in less than 10 4s. 5.3 Unbalanced signal input Reference measurements for verification of the parameters at the unbalanced input side should be made in accordance with the technology used and are not
41、 specified in this International Standard. V A , V B , k 0,3 V V A , V B , U +0,3 V Data circuits Mark, 1 Space, 0 Control and timing circuits OFF ON VISO/IEC 9549:1990(E) 4 BSI 01-2000 6 Isolated receiver characteristics 6.1 Balanced signal input A receiver component is measured in accordance with
42、the measurement arrangements shown in subclause9 of ISO 8482 (without termination). The receiver component may be supplied for the measurements by an appropriate single-rail power supply for the unbalanced output side and the balanced input side. Alternatively, a floating power supply may be used fo
43、r the balanced input side. The tests are made for either binary state. 6.1.1 Input sensitivity As in subclause 9.1 of ISO 8482. 6.1.2 Input balance As in subclause 9.2 of ISO 8482. 6.2 Cable termination option The cable termination resistance shall not be less than 120 7. 6.3 Circuit failure detecti
44、on option The interpretation of a fault condition by an isolated receiver depends on its application. The following two types, as specified in clause 9 of CCITT Recommendation V.11, shall be selectable: 6.4 Unbalanced signal output Reference measurements for verification of the parameters at the unb
45、alanced output side should be made in accordance with the technology used and are not specified in this International Standard. 7 Fault condition tests The components are tested according to the measurement arrangements shown in subclause 10 of ISO8482. No damage shall occur due to a single fault co
46、ndition. 7.1 Generator short circuit As in subclause 10.1 of ISO 8482. 7.2 Generator contention As in subclause 10.2 of ISO 8482. 7.3 Generator current limitation As in subclause 10.3 of ISO 8482. 7.4 Transient over-voltage As in subclause 10.4 of ISO 8482. 8 Interconnection configuration Shielded t
47、wisted pair cables with wires 0,4 mm to 0,6 mm in diameter are recommended to be used in all configurations. Examples of configurations are illustrated in CCITT Recommendation V.11, Figure 3, for point-to-point applications and in ISO 8482, Figure 2 and Figure 3, for multipoint applications, respect
48、ively. 9 Optocoupler component isolation The resistance between the unbalanced input side and the balanced output side of an isolated generator, and between the balanced input side and the unbalanced output side of an isolated receiver shall be 10 67 at 500 V (a.c.) under operational conditions. The
49、 optocoupler components, when connected to their associated power supplies, as shown in Figure 3, shall withstand without breakdown a voltage of2,5kV(rms) for a minimum of 1 min. Type 1: Data circuits assume a binary 1 state. Control and timing circuits assume an OFF condition. Type 2: Data circuits assume a binary 0 state. Control and timing circuits assume an ON condition.ISO/IEC 9549:1990(E) BSI 01-2000 5 NOTEHigher voltage may apply where safety is under consideration. (e.g. IEC 950) 10 Signal distortion The ind
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