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1、BRITISH STANDARD BS ISO/IEC 8482:1993 Implementation of ISO/IEC 8482:1993 Information technology Telecommunications and information exchange between systems Twisted pair multipoint interconnections Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c)
2、 BSI BS ISO/IEC 8482:1993 This British Standard, having been prepared under the direction of the Information Systems Technology Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 August 1994 BSI 11-1999 The following BSI references relate
3、 to the work on this standard: Committee reference IST/6 Draft for comment 92/66586 DC ISBN 0 580 23227 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Information Systems Technology Standards Policy Committee (IST/-) to Technical Comm
4、ittee IST/6, upon which the following bodies were represented: British Computer Society British Telecommunications plc CCTA (the Government Centre for Information Systems) Digital Equipment Co. Ltd. IBM United Kingdom Ltd. Information Systems Committee of the Universities Funding Council Institution
5、 of Electrical Engineers International Computers Limited Logica UK Ltd. Ministry of Defence Rank Xerox Ltd. Swift Project Consortium Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
6、ISO/IEC 8482:1993 BSI 11-1999i Contents Page Committees responsibleInside front cover National forewordii Forewordiii Text of ISO/IEC 84821 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/IEC 8482:1993 ii BSI 11-1999 National foreword
7、 This British Standard reproduces verbatim ISO/IEC 8482:1993 and implements it as the UK national standard. It supersedes BS 7248:1990, which is withdrawn. This British Standard is published under the direction of the Information Systems Technology Standards Policy Committee whose Technical Committe
8、e IST/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.
9、 NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, Publications, 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 responsi
10、ble for their correct 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, the ISO/IEC title page, pages ii to iv, pages 1 to 16 and a back cover. This
11、 standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun she
12、ffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/IEC 8482:1993(E) ii BSI 11-1999 Contents Page Forewordiii 1Scope1 2Normative reference1 3Definitions1 4Symbolic representation of an interchange circuit4 5Interconnection configurations4 6Load on the multipoint medium4
13、7Polarities and significant levels7 8Generator characteristics7 9Receiver characteristics7 10Fault condition tests8 11Environmental constraints8 12Component compatibility8 Annex A (informative) Guidelines and explanatory notes12 Annex B (informative) Guidance on a.c. loading measurement16 Figure 1 S
14、ymbolic representation of interchange circuit3 Figure 2 Two-wire multipoint configuration5 Figure 3 Four-wire multipoint configuration5 Figure 4 Current limit of 1,0 UL6 Figure 5 Input current/voltage measurement6 Figure 6 UL value determination6 Figure 7 Open circuit voltage measurement9 Figure 8 O
15、ffset voltage measurement9 Figure 9 Terminated output voltage measurement9 Figure 10 Rise time measurement10 Figure 11 Input voltage range10 Figure 12 Input balance measurement11 Figure 13 Generator short-circuit test11 Figure 14 Generator contention test11 Figure A.1 Generator contention with singl
16、e sourcing generator14 Figure A.2 Generator contention with multiple sourcing generators14 Figure B.1 Reflection attenuation measurement16 Table 1 Receiver differential significant levels7 Table 2 Compatibility with ITU-T Recommendation V.118 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04
17、:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/IEC 8482:1993(E) BSI 11-1999iii Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members
18、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 organiz
19、ations, 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 t
20、o 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 8482 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecommunications
21、and information exchange between systems. This second edition cancels and replaces the first edition (ISO 8482:1987), which has been technically revised. Annex A and Annex B of this International Standard are for information only. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+0
22、0:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/IEC 8482:1993(E) BSI 11-19991 1 Scope 1.1 This International Standard specifies the physical medium characteristics for twisted pair multipoin
23、t interconnections in either 2-wire or 4-wire network topology in order to provide for half duplex or duplex data transmission capability, respectively; a binary and bi-directional signal transfer of the interconnected endpoint systems; the electrical and mechanical design of the endpoint system bra
24、nch cables and the common trunk cable, which may be up to 1 200 m in length; the component measurements of the integrated circuit type generators and receivers within the endpoint systems; the applicable data signalling rate up to 12,5 Mbit/s. 1.2 The defined electrical component characteristics and
25、 measurements are in close conformance with the twisted pair point-to-point characteristics given in ITU-T Recommendation V.11. 1.3 This International Standard does not describe a complete physical interface and has no functional interface characteristics, such as number of interchange data and cont
26、rol circuits; type, size and pin allocation of the endpoint system and branch trunk cable connectors; data and control signal encoding; time relations between signals on the interchange circuits; mode of synchronous or asynchronous transmission; signal quality for transmission and reception. 1.4 Thi
27、s International Standard does not specify special environmental conditions, such as galvanic isolation, electromagnetic interference (EMI), radio frequency interference (RFI), and human safety. This may form the subject of a future amendment. 1.5 This International Standard is primarily a component
28、specification. It is not sufficiently specified for satisfactory interoperation in all possible configurations. It is the responsibility of implementors to ensure that their intended configuration will allow satisfactory interoperation. 1.6 This International Standard may be combined with any approp
29、riate set of functional and additional environmental characteristics so as to meet the practical data transmission requirements in the field of local or wide area networks. 2 Normative reference The following ITU-T Recommendation contains certain provisions which, through reference in this text, con
30、stitutes provisions of this International Standard. At the time of publication, the edition indicated was valid. All CCITT Recommendations and International Standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility
31、 of applying the most recent edition of the recommendation indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. The ITU-T Secretariat maintains a list of currently valid ITU-T Recommendations. ITU-T Recommendation V.11:1988, Electrical characteristic
32、s for balanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications. 3 Definitions For the purposes of this International Standard the following definitions apply: 3.1 balanced interchange circuit an interchange circuit which uses
33、two conductors and the differential mode voltage for transmitting signals 3.2 common mode ejection ratio (CMRR) for balanced interchange circuits, the ratio of an applied common mode voltage, Vcm to the resulting transverse voltage Vtr (same as the differential mode voltage) the ratio is normally ex
34、pressed in decibels as NOTEThe rejection ratio depends upon the circuit termination and should be measured while terminated in normal use. 3.3 common mode voltage one half the vector sum of the voltages between each conductor of a balanced interchange circuit and ground or other stated voltage refer
35、ence NOTEThis voltage may be a transmitted (or received) signal or noise intereference. In the latter case, this voltage is generally not the same as the voltage, which is sometimes referred to as common mode voltage, that may exist (in a common mode) between the ends of an interchange circuit pair
36、as a result of induction or ground-reference potential difference. CM RR20 Vcm Vtr - -log= Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/IEC 8482:1993(E) 2 BSI 11-1999 3.4 cross-talk loss (near end) for two interchange circuits used fo
37、r transmission in opposite directions, the ratio, expressed in decibels, of the voltage transmitted on one interchange circuit to the resulting voltage (cross-talk) at the receive end of the other interchange circuit 3.5 cross-talk loss (far end) for two interchange circuits used for transmission in
38、 the same direction, the ratio, expressed in decibels, of the voltage transmitted on one interchange circuit to the resulting voltage (cross-talk) at the receive end on the other interchange circuit 3.6 differential mode voltage the vector difference of the voltages between each conductor of a balan
39、ced interchange circuit and ground or other stated voltage reference NOTEThe differential mode voltage is commonly referred to as the transverse mode voltage. 3.7 environmental conditions those characteristics of the electrical or physical environment, for example EMI, ground potential difference ma
40、gnetic fields, altitude, temperature, etc., which may affect the operation, with respect to interchange circuits, of a DTE or DCE 3.8 galvanic isolation the existence of a element that is non-conductive with respect to the conductivity of common mode voltage, between the equipment containing a gener
41、ator and the equipment containing a receiver of an interchange circuit 3.9 generator the component of an interchange circuit that is the source of the transmitted signal NOTEThe term generator is used interchangeably with the term driver. 3.10 generator offset voltage the d.c. component of half the
42、vector sum of the voltages between each conductor of a balanced interchange circuit generator and its signal ground reference NOTEThe d.c. component of half the vector sum of the voltages is the same as the arithmetic mean of the d.c. voltages in the above. 3.11 ground signal the generator/receiver
43、signal voltage reference 3.12 ground earth the voltage reference established by conductive components having a conductive path to earth in the vicinity of the equipment including the generator/receiver NOTEEarth ground is generally synonymous with, and the same as, frame or building ground or protec
44、tive ground. 3.13 ground potential difference the difference between the signal ground potentials of the generator and the receiver of an interchange circuit the potential is the same as the difference in the earth ground potential difference only if the signal ground is connected to earth ground at
45、 both the generator and the receiver 3.14 induced noise an interfering voltage that is introduced into an interchange circuit by electromagnetic induction from currents in other conductors for balanced interchange circuits induced voltages generally appear in the common mode 3.15 interchange circuit
46、 the circuit, including a generator, a receiver and interconnecting media, that provides for the interchange of signals across an interface, for example DTE/DTE, DTE/DCE, DCE/DCE 3.16 interchange point the point in an interchange circuit at which the specified electrical characteristics of the circu
47、it apply and should be measured NOTEThe interchange point usually defines the line of demarcation between equipment and is usually the location of an interface connector. 3.17 receiver the component of an interchange circuit that provides for the detection of interchange circuit signals at the recei
48、ving equipment Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 23 04:42:14 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/IEC 8482:1993(E) BSI 11-19993 3.18 rise time the time required for a generator output signal voltage to change from a value characteristic of one state to a value characteris
49、tic of a second state it is most often specified as the time for the signal voltage to pass between the 10 % and 90 % points of the wave form NOTE 1Rise time is normally dependent on the load and is usually specified for a specific test termination. NOTE 2For unbalanced generators, the time for the change from an ON or active state to an OFF or inactive state is sometimes referred to as the “fall time”. 3.19 site conditions the environmental conditions for a given site 3.20 surge voltage resistance t