1、BRITISH STANDARD BS ISO 4903:1989 Implementation of ISO 4903:1989 Information technology Datacommunication 15-pole DTE/DCE interface connector and contact number assignmentsBSISO4903:1989 This British Standard, having been prepared under the directionof the Information Systems Technology StandardsPo
2、licy Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 31 December 1990 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference IST/6 Draft for comment 90/61224 DC ISBN 0 580 19298 9 Committees responsible for this Britis
3、h Standard The preparation 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 Teleco
4、mmunications plc Department of Trade and Industry (National Physical Laboratory) EEA (the Electronics and Business Equipment Association) Electricity Supply Industry in England and Wales Information Technology Users Standards Association Joint Network Team National Computing Centre Ltd. National Hea
5、lth Services OFTEL (Office of Telecommunications) Post Office Telecommunication Engineering and Manufacturing Association User Standards Forum for Information Technology (Institute of Data Processing Management) Amendments issued since publication Amd. No. Date CommentsBSISO4903:1989 BSI 10-1999 i C
6、ontents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO 4903 1BSISO4903:1989 ii BSI 10-1999 National foreword This British Standard reproduces verbatim ISO 4903:1989 and implements it as the UK national standard. This British Standard supersedes BS 6623-3
7、:1986 which is withdrawn. This British Standard is published under the direction of the Information Systems Technology Standards Policy Committee whose Technical Committee IST/6 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any en
8、quiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from BSI Sales Department, BSI, Linford Wo
9、od, 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 correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of p
10、ages This document comprises a front cover, an inside front cover, pages i and ii, theISO title page, pages ii to iv, pages1 to 18 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the insi
11、de front cover.ISO4903:1989 (E) ii BSI 10-1999 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Connector 2 5 Assignment of contact numbers 2 6 Connector shielding 2 7 Interconnecting configurations for mixed use of X.26, X.26 and V.28 electrical characteristics 2 Anne
12、x A (informative) Diagrams for finger clearance 8 Annex B (informative) Generator/receiver interconnecting configurations 9 Annex C (informative) Interworking requirements with V.28 circuits 15 Figure 1 DTE connector 4 Figure 2 DCE connector 5 Figure 3 Contact spacing dimensions 6 Figure 4 Male cont
13、act 7 Figure 5 Female contact 7 Figure A.1 Maximum DTE connector outline 8 Figure A.2 Minimum DCE connector spacing 9 Figure B.1 X.20 interconnection configuration for X.26 DTE/X.26 DCE 10 Figure B.2 X.20 interconnection configuration for X.27 DTE/X.26 DCE 11 Figure B.3 X.21 interconnection configur
14、ation for X.26 DTE/X.27 DCE 12 Figure B.4 X.21 interconnection configuration for X.27 DTE/X.27 DCE 13 Figure B.5 Cable length against risetime 14 Figure C.1 L-pad attenuator for protection of X.26 receiver 17 Figure C.2 Interconnection configuration with 25/15-pole adapter 17 Figure C.3 Adapter wiri
15、ng diagram 18 Table 1 Assignment of contact numbers for interface CCITTRecommendationsX.20, X.21, and X.22 3 Table 2 List of interchange circuits 3ISO4903:1989 (E) BSI 10-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
16、 (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations,
17、governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated t
18、o the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 4903 was prepared by Technical Committee ISO/TC 97, Inf
19、ormation processing systems. This second edition cancels and replaces the first edition (ISO 4903:1980), of which it constitutes a minor revision; certain terms have been aligned with the terms and definitions used by IEC.iv blankISO4903:1989 (E) BSI 10-1999 1 1 Scope This International Standard spe
20、cifies the 15-pole connector and the assignment of contact numbers at the interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) where CCITT 1)Recommendations X.24, X26, and X.27 are applicable. International Standard ISO/IEC 4903 additionally provides the dimen
21、sions of the connector housing, as well as the recommended means of providing a locking device (latching block) and connector shielding. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At t
22、he 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 of applying the most recent editions of the standards indicated below. Members of IEC and ISO
23、 maintain registers of currently valid International Standards. ISO 261:1973, ISO general purpose metric screw threads General plan. ISO 2110:1989, Information technology Data communication 25-pole DTE/DCE interface connector and contact number assignments. CCITT Recommendation V.28:1989, Electrical
24、 characteristics for unbalanced double-current interchange circuits. CCITT Recommendation X.20:1989, Interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for start-stop transmission services on public data networks. CCITT Recommendation X.21:1989, Interface be
25、tween data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for synchronous operation on public data networks. CCITT Recommendation X.22:1989, Multiplex DTE/DCE interface for user classes 3-6. CCITT Recommendation X.24:1989, List of definitions for interchange circuits between d
26、ata terminal equipment (DTE) and data circuit-terminating equipment (DCE) on public data network. CCITT Recommendation X.26 (or V.10):1989, Electrical characteristics for unbalanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communicati
27、ons. CCITT Recommendation X.27 (or V.11):1989, Electrical characteristics for balanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications. IEC Publication 50(581):1978, International Electrotechnical Vocabulary Chapter 581: Elect
28、romechanical components for electronic equipment. IEC Publication 807-2:1985, Rectangular connectors for frequencies below 3 MHz Part 2: Detail specification for a range of connectors with round contacts Fixed solder contact types. 3 Definitions The following definitions have been taken from IECPubl
29、ication 50(581):1978. 3.1 cable adaptor a part of a connector or an accessory consisting of a rigid housing for attachment to the connector body. It may incorporate provision for a cable clamp or seal for terminating screens and provide shielding from electrical interference. It may be straight or a
30、ngled 3.2 connector housing a part of a connector into which the insert and contacts are assembled 3.3 contact arrangement the number, spacing and configuration of contacts in a component 3.4 female contact a contact intended to make electrical engagement on its inner surface and which will accept e
31、ntry of a male contact 3.5 intermateable connectors two connectors are intermateable when they are capable of being connected electrically and mechanically but without regard to their performance and intermountability 3.6 locking device a feature incorporated in certain components to provide mechani
32、cal retention of their mating part 1) International Telegraph and Telephone Consultative Committee.ISO4903:1989 (E) 2 BSI 10-1999 3.7 male contact a contact intended to make electrical engagement on its outer surface and which will enter a female contact 3.8 (n-pole-)connector a component which term
33、inates conductors for the purpose of providing connection and disconnection to a suitable mating component 4 Connector Figure 1 to Figure 5 illustrate the 15-pole interface connector. Only those dimensions that are essential to mating are shown. Figure 1 illustrates the DTE connector which has 15 ma
34、le contacts in a connector housing. Figure 2 illustrates the DCE connector which has 15 female contacts in a connector housing. The connector housing on the DCE connector is dimensioned to fit inside the connector housing on the DTE connector (see Figure 1 and Figure 2). Contact numbering is specifi
35、ed in Figure 1 and Figure 2. Figure 3 illustrates the dimensions for the contact spacing. Figure 4 and Figure 5 illustrate the dimensions for the male and female contacts respectively. The DCE connector shall be equipped with a locking device consisting of two latching blocks as specified in Figure
36、2. Due to the fact that the latching blocks have threaded holes which can act as nuts, the DTE connector may be equipped either with lever devices for latching to the latching blocks on the DCE connector or with screws that fit into the threaded holes in the latching blocks. The thread of the latchi
37、ng blocks shall be M3 as specified in Figure 2. Sufficient connector dimensions are provided in this International Standard to ensure intermateable connectors. They are consistent with the detailed connector specification in IEC Publication 807-2. In Annex A, diagrams for finger clearance areas are
38、given to provide guidance for equipment designers. Figure A.1 shows the maximum DTE connector outline including all means for latching to the latching blocks. Figure A.2 shows the minimum DCE connector spacing when multiple interface arrangements are used. 5 Assignment of contact numbers The assignm
39、ent of contact numbers for the interchange circuits specified in CCITT Recommendations X.20, X.21 and X.22 is given in Table 1 for implementations using X.26 and X.27 electrical characteristics. Additionally, contact 1 is reserved for connection of the shield of shielded interconnecting cable. Table
40、 2 gives a list of interchange circuits and their description. Their provision and use shall be in conformity with the corresponding CCITT DCE Recommendations. 6 Connector shielding Connector shielding is optional. If it is used, for example due to national regulations, etc., it shall be accomplishe
41、d by the use of metallic connector housings on both the DTE connector and the DCE connector. 7 Interconnecting configurations for mixed use of X.26, X.26 and V.28 electrical characteristics Considerations for the interworking of equipment implementing X.26 on one side of the interface with equipment
42、 implementing X.27 on the other side of the interface are given in Annex A.2 of CCITT Recommendations X.26 and X.27. In addition, the definition of the category 1 and 2 receiver configurations is provided in V.10. Guidance concerning possible interconnecting configurations applicable to the X.20 and
43、 X.21 interfaces is provided in Annex B. Guidance concerning the necessary adaptation when there is a need for X.20 DCE implementing X.26 characteristics to interwork with X.20 DTE implementing V.28 characteristics is given in Annex C. Any adapters required to accomplish the interworking with equipm
44、ent meeting the V.28 requirements shall be provided with equipment meeting the requirements of this InternationalStandard, i.e., the X.20/X.26 DCE. No revisions or modifications shall be required in the equipment using V.28 electrical characteristics.ISO4903:1989 (E) BSI 10-1999 3 Table 1 Assignment
45、 of contact numbers for interface CCITT Recommendations X.20, X.21, and X.22 Table 2 List of interchange circuits Contact number 6) Interchange circuit assignment X.20 2) X.21 3) X.22 X.26 X.27 5) X.26 4),5) X.27 5) X.27 5) 1 1) 1) 1) 1) 1) 2 T T(A) T T(A) T(A) 3 C C(A) C(A) 4 R R(A) R(A) R(A) R(A)
46、5 I(A) I(A) I(A) 6 S(A) S(A) S(A) 7 X/B(A) 7) X/B(A) 7) F(A) 8 G G G G G 9 Ga T(B) Ga T(B) T(B) 10 Ga C(B) C(B) 11 Gb R(B) R(B) R(B) R(B) 12 I(B) I(B) I(B) 13 S(B) S(B) S(B) 14 X/B(B) 7) X/B(B) 7) F(B) 15 Reserved for future international use NOTE 1Contact 1 is assigned for connecting the shields be
47、tween tandem sections of shielded interface cable. The shield may be connected either to protective ground or to signal ground at either the DTE or DCE or both in accordance with national regulations. Signal ground may be further connected to protective ground in accordance with national safety regu
48、lations. Caution should be exercised to avoid establishment of ground loops carrying high currents. NOTE 2DTEs may employ either X.26 or X.27 electrical characteristics to operate with DCEs using X.26 electrical characteristics in accordance with X.20. NOTE 3DTEs may employ either X.26 or X.27 elect
49、rical characteristics to operate with DCEs using X.27 electrical characteristics in accordance with X.21 for data signalling rates of 9,6 kbit/s and below. Only X.27 applies above 9,6 kbit/s. NOTE 4The assignment of contact numbers has been chosen considering interworking between X.26 DTE and X.27 DCE using the considerations given in annex 2 of Recommendations X.26 and X.27. NOTE 5Where balanced circuits are concerned, the associated pairs are designated “A” and “B” in X.27. NOTE 6The a
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