1、TIA STANDARD Electrical Characteristics of Generators and Receivers for Use in Balanced Digital Multipoint Systems TIA-485-A (Revision of EIA-485) MARCH 1998 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Representing lhe telecornmunicalions industry in ssriom%ion wilh lhe FJcclronic Industries Alliance El
2、sctrsnk industri6% Alliance Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE TIA Engineering Standards and Publications are designed to serve the public interest through eliminatin
3、g misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for their particular need. The existence of such Standards and Publications shall not in
4、 any respect preclude any member or non-member of TIA fi-om manufacturing or selling products not conforming to such Standards and Publications. Neither shall the existence of such Standards and Publications preclude their voluntary use by Non-TIA members, either domestically or internationally. Sta
5、ndards and Publications are adopted by TIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, TIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. Further det
6、ails of the development process are available in the TIA Engineering Manual, located at This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safe
7、ty and health practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 3-3498-RF1, formulated under the cognizance of the TIA TR-30.2 Subcommittee on DTE-DCE Interfaces and Protocols.) This Document was reaffirmed by the American National St
8、andards Institute (ANSI) on March 28,2003 and by the TIA. Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1998 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 U.S.A. PRICE: Please refer to current Catalog of TIA TELECOMMUNICATIONS INDUSTRY ASSOCIATION STANDARDS AN
9、D ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) or search online at http:/www.tiaonline.org/standards/search-n-order.cfm All rights reserved Printed in U.S.A Copyright Electronic Industries Alliance Provided by IHS under l
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21、EREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright Electronic Industries Alliance Provided by IHS
22、 under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-EIA TIA-485-A-ENGL 1998 W 3234600 0597956 705 I TEECOMMUNILIATIOMS AN SI/ TIA/EIA-48 5- A- 1998 Approved: March 3, 1998 TIA/EIA STANDARD Electrical Characteristics of Generators and Receive
23、rs for Use in Balanced Digital Multipoint Systems TIAIEIA-485-A (Revision of EiA-485) MARCH 1998 TELECOMMUNICATIONS INDUSTRY ASSOCIATION I INDUSlY ASSOCLATION Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without
24、license from IHS-,-,-STD-EIA TIA-485-A-ENGL 1998 m 3234600 0597957 641 m NOTICE TIA/EiA Engineering Standars and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeabfiv and improvement of product
25、s, and assisting the purchaser in selecthg and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of TIA/EiA from manufacturing or selling products not conforming to such Stan
26、dards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than TIA/EzA members, whether the standard is to be used either domestidy or internationally. Standards and Publications are adopted by WELA in accordance with the American
27、National Standards Institute (ANSI) patent policy. By such action, TLA/EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This Standard does not purport to address ali safety problems associated with its
28、use or ali applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to detede the applicability of regulatory limitations before its use. (From Standards Proposal No. 3498, formulated under the cognizance of th
29、e TR-30.2 Subcommittee on DTE-DCE Interfaces). Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION 1998 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to current Catalog of EIA, JEDEC, and “LA STANDARDS and ENGINEERING PUBLICATIONS or call Global E
30、ngineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) All rights reserved Printed in U.S.A. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANS ITTINEIA-485-
31、A ELECTRICAL CHARACTERISTICS OF GENERATORS AND RECEIVERS FOR USE IN BALANCED DIGITAL MULTIPOINT SYSTEMS (From TIA/EIA Standards Proposal No . 349% formulated under the cognizance of TIA Subcommittee TR-30.2 on Data Transmission Interfaces) CONTENTS Page 1 SCOPE . 1 2 DEFINITIONS. SYMBOLS AND ABBREVI
32、ATIONS 1 3 APPLICABILI PI 2 4 ELECTRICAL CHARACTERISTICS 3 4.1 4.1 . 1 4.1.2 Unit load characteristics 5 dc Unit load specification . 5 ac Load characteristics 6 4.2 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 Generator characteristics 7 Differential output voltages with common-mode loading 8 Short-ci
33、rcuit output characteristics . 9 Transient over voltage tolerance 1 0 Output signal waveform . Open circuit output voltages . 7 Differential and offset output voltages 7 Off-state output current 9 1 0 4.3 Receiver characteristics 10 12 4.3.3 Input balance measurements . 12 4.3.4 4.3.5 Transient over
34、 voltage tolerance 13 4.3.1 Input voltage ranges 4.3.2 Input thresholds . 12 Receiver unit load test . 13 . 4.4 Transceiver characteristics 13 4.5 System requirements 13 4.5.1 4.5.2 Cable temination . 14 4.5.3 Total load limit 14 Balanced interconnecting media characteristics . 13 4.5.4 Fail-safe op
35、eration . 14 Annex A (informative) . 15 Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD.EIA TIA-45-A-ENGL L998 3234600 0597959 IJ+ m ANSITTIAlEIA-485-A A.l Multipoint system configu
36、ration 15 A.2 Data signaling rate vs . cable length 15 A.3 Stub lengths . 15 A.4 A.4.1 A.4.2 Configuration “A“ 15 A.4.3 Configuration “B“ 16 A.4.4 Shield ground . 16 Optional grounding arrangements 15 Signal common (Ground) . 15 A.5 References . 16 Copyright Electronic Industries Alliance Provided b
37、y IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-EIA TIA-485-A-ENGL 1998 3234b00 05977b0 136 = ANSITTINEIA-485-A FOREWORD (This foreword is not part of this Standard.) This Standard was formulated under the cognizance of TIA Subcommit
38、tee TR-30.2 on Data Transmission Interfaces. This Standard specifies generators and receivers capable of operating in balanced digital multipoint systems. The parameter values specified in this Standard are similar to those in TINEIA-422-B. These values allow generators and receivers to be designed
39、that can be used to meet the requirements of both standards. No technical changes have been incorporated into TINEIA-485-A which will create compatibility problems with equipment conforming to previous versions of this Standard (EIA RS-485). The Telecommunications Systems Bulletin TSB-89 contains ap
40、plication guidelines on TINEIA-485-A. Topics covered include: data signaling rate vs. cable length, stub length, configurations, and other important considerations. This Standard is compatible with ISOAEC 8482:1993 Information Technology - Telecommunications and information exchange between systems
41、- Twisted pair multipoint interconnections. Annex A of this Standard is informative and provides a minimum set of guidelines for application, and is not considered part of this Standard. iii Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction
42、or networking permitted without license from IHS-,-,-STD-EIA TIA-4BS-A-ENGL 3998 3234600 0597963 O72 ANS ITTINE IA-485-A 1 SCOPE This Standard specifies the electrical characteristics of generators and receivers that may be employed when specified for the interchange of binary signals in multipoint
43、interconnection of digital equipment. When implemented within the guidelines of this Standard, multiple generators and receivers may be attached to a common interconnecting cable. An interchange system includes one or more generators connected by a balanced interconnecting cable to one or more recei
44、vers and terminating resistors. The electrical characteristics of the circuit are specified in terms of the required voltage, current, and resistance values obtained by measurements at the equipment interconnect points. This Standard does not specify other characteristics, such as signal quality, ti
45、ming, protocol, pin assignments, power supply voltage, operating temperature range, etc., that are essential for proper operation of interconnected equipment. Any devices complying with this Standard shall do so within the ranges of those factors appropriate for the device operation, such as power s
46、upply voltages, and ambient temperature. It is intended that this Standard be referenced by other standards and specifications that specify the additional characteristics necessary to assure satisfactory interoperation of equipment. This Standard is compatible with ISOAEC 8482:1993 Information Techn
47、ology - Telecommunications and information exchange between systems - Twisted pair multipoint interconnections. 2 DEFINITIONS, SYMBOLS AND ABBREVIATIONS For the purposes of this Standard, the following definitions, symbols and abbreviations apply: 2.1 Common-mode voltage (Vcm), one half of the sum o
48、f the voltages between each conductor of a balanced interchange circuit and ground. The common-mode voltage is the sum of ground potential difference, generator offset voltage and longitudinally coupled noise voltage. 2.2 where T is the minimum interval between two significant instants. Data signali
49、ng rate, expressed in the units bit/s (bits per second), is defined as 1/T 2.3 respect to common (C). Differential, the signal is the voltage difference between the A and B, not with 2.4 transmitted signal. Generator (Driver), the component of an interchange circuit that is a source of the 2.5 potential between the active generator and a receiver of an interchange circuit. Ground potential
