1、TIA/EIA TELECOMMUNICATIONS SYSTEMS BULLETIN Test Procedure for Evaluation of 2- Wire 4-Kilohertz Voiceband Duplex Modems TSB-38 REAFFIRMED JULY 2002 DECEMBER 1994 TELECOMMUNICATIONS INDUSTRY ASSOCIATION The Teleconmiunications Industry Association represents the conmiunications sector of NOTICE TIA/
2、EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the
3、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 Standards and Publications, nor shall the existence of such Standards and Publicatio
4、ns preclude their voluntary use by those other than TIA/EIA members, whether the standard is to be used either domestically or internationally. Standards, Publications and Bulletins are adopted by EIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action,
5、TIA/EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Publication, or Bulletin. Technical Bulletins are distinguished from TIA/EIA Standards or Interim Standards, in that they contain a compilation of engineering data
6、or information useful to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be accept
7、able to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this Bulletin are encouraged to do so. It is the intention of the formulating committee to revise and
8、update this Bulletin from time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (From Project No. 3-3175, formulated under the cognizance of the TIA TR-30.3 Subcommittee on Data Communications Network Interfaces) T
9、his document was reaffirmed by the Telecommunications Industry Association on June 1 O, 2002. Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1994 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 U.S.A. PRICE: Please refer to the current Catalog of ELECTRONIC INDUS
10、TRIES ALLIANCE STANDARDS and ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1 -800-854-71 79) International (303-397-7956) All rights reserved Printed in U.S.A. NOTICE OF DISCLAIMER AND LIMITATION OF LIABILITY The document to which this Notice is affixed has been prep
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19、OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. EIA TSB38 94 3234600 0567203 527 = rIA/EIA rELECOMMUNI CATIONS SYSTEMS BULLETIN rest Procedure for Evaluation of 2-Wire #-Kilohertz Voiceband Duplex Modems TSB38 DECEMBER 1994 TELECOMMUNICATIONS INDUST
20、RY ASSOCIATION EIA TSB38 94 = 3234600 O567202 463 H NOTICE TINEIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeabjity and improvement of products, and assisting the
21、 purchaser in selecting 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 TIAIEIA from manufacturing or selling products not conforming to such Standards and Publicati
22、ons, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than TIA/?W members, whether the standard is to be used either domestically or internationally. Recommended Standards, Publications and Bulletins are adopted by WEiIA in accordance with the Am
23、erican National Standards Institute (ANSI) patent policy. By such action, TIA/EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Recommended Standard, Publication or Bulletin. Technical Bulletins are distinguished from TINEIA Rec
24、ommended Standards or Interh Standards, in that they contain a compilation of engineering data or information useful to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discou
25、rage other approaches that similarly represent good engineering pdce, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this Bullet
26、in are encouraged to do so. It is the intention of the formulating committee to revise and update this Bulletin from time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. Published by -0MMUNICATIONS INDUSTRY ASSOCI
27、ATION 1994 Standards and Technology Department 2001 Pennsylvania Ave. N.W., Washington, D.C. 20006 PRICE Please refer to the current Catalog of EU, JEDEC and TIA STANDARDS and ENGI“G PUBLICATIONS or call Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) AU ri
28、ghts reserved Printed in U.S.A. CONTENTS EIA TSB38 94 3234600 0567204 236 TSB-38 PAGE SCOPE . i NORMAllVE REFERENCES 2 DEFINmONS . 4 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.1 1 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 3.25 3.26 3.27 3.28 3.29 3.30 3.31 3.32 3.33 3.34 async
29、hronous . 4 bit . 4 bit-error ratio; BER . 4 block 4 block-error ratio; BLER 4 British Telecom Ziv-Lempel; BTLZ . 4 buffered mode; normal mode . 4 byte 4 character 4 compression mode . 5 compression ratio . 5 data terminal equipment; DTE . 5 dictionary size 5 direct mode 5 duplex modem; full duplex
30、modem . 5 error control mode 5 FOX message . 5 half duplex modem 6 impairment combination 6 line rate; data signalling rate . 6 maximum string length . 6 message-error ratio; MER 6 parity bit . 6 port rate 6 RTS/CTS flow control; hardware flow control . 6 signal converter 6 synchronous . 6 synchrono
31、us mode . 7 test channel . 7 test loop combination; TLC 7 throughput 7 two way transfer 7 XON/XOFF flow control; software flow control 7 one way transfer . 6 i TSB-38 EIA TSB3 94 3234b00 0567205 172 REQUI REM ENTS . u 8 4.1 Network simulator . 8 4.2 DTEs 8 NElWORK MODEL COVERAGE CONSIDERATIONS . TES
32、T PROCEDURES 13 6.1 6.2 6.3 6.4 6.5 6.6 Throughput vs . network model coverage 15 File-based with compression . 16 6.1.1 6 .I . 2 File-based without compression 18 22 Throughput vs . file type . Error ratio vs . network model coverage . 25 Bit- and block-error ratio vs . network model coverage 26 6.
33、3.1 6.3.2 Message-error ratio vs . network model coverage . 29 Connect reliability vs . test loop combinations 32 Character echo delay 35 Block acknowledge delay . 38 .ANNEX A (Normative) . 41 DTE Verification Procedures . 41 A ANNEX B (Normative) . 43 Description of Data Files 43 B ANNU( C (Informa
34、tive) . 44 Characteristics of Data Files . 44 ANNEX D (Informative) 47 Determination of Reference Throughput Values . 47 ANNEX E (Informative) . 49 C D E Error Rate Estimation . . 49 ? A EIA TSB38 74 3234b00 0567206 O09 TSB-38 ANNEX F (Informative) 55 F Data Reporting Format and Interpretation of Re
35、sults 55 Throughput vs . file type 62 Error ratio vs . network model coverage 64 Connect reliability vs . test loop combinations . 73 F.l F.2 F.3 F.4 F.5 F.6 Throughput vs . network model coverage . 55 Character echo delay . 78 Block acknowledge delay 82 ANNEX G (Infornative) . 86 G Call Initiation
36、Considerations 86 ANNEX H (Informative) . 88 H RTS/CTS Flow Control 88 ANNEX I (Informative) . 89 I Modem Overview 89 ANNEX J (Informative) . 98 J Minimizing test time . 98 ANNEX K (Informative) . 101 K Circuit Identification Cross-Reference . 101 iii . EIA TSB38 94 3234600 O567207 T45 E TSB-38 FORE
37、WORD (This Foreword is not part of this Bulletin) This document is intended to provide a common basis for comparison of mo- dem performance. Different test procedures described in this Bulletin empha- size different modem applications. The Throughput versus network model cov- erage test procedure, f
38、or example, is important for evaluating modem per- formance when used in asynchronous file transfer applications; the Error Rate versus Network Model Coverage test procedure is important for evaluating mo- dem performance in synchronous or asynchronous network applications. No single test is compreh
39、ensive enough to determine which modem will per- form best in all applications, but this series of tests permits the gathering of sufficient data on a modem to determine its strengths and weaknesses. Individual users shall decide which factors are important for their particular application or applic
40、ations. There are 11 annexes in this Bulletin. Annexes A and B are normative and are considered part of this Bulletin; annexes C through K are informative and are not considered part of this Bulletin. a EIA TSB38 94 W 3234600 0567208 981 TSB-38 INTRODUCTION Because of the lack of consistent test pro
41、cedures and criteria for interpretation of results, modem performance evaluations historically have resulted in widely varying modem comparisons. TIA TR-30.3 has created this Telecom- munications Systems Bulletin to resolve this problem. This Bulletin provides a consistent set of repeatable test pro
42、cedures designed to characterize the performance of modems. This is achieved by stating the precise configuration of all the required test equipment, then giving step-by- step instructions for performing each test. This document also suggests some formats for analyzing, interpreting, and presenting
43、the results. TSB-38 (This page left blank.) vi EIA TSB38 94 3234600 05672110 53T TSB-38 TEST PROCEDURE FOR EVALUATION OF 2-WIRE BER: ratio of erroneous bits to total bits received at a 3.4 block: group of contiguous bits. 3.5 received at a DTE-to-modem interface. block-error ratio; BLER: ratio of er
44、roneous blocks to total blocks 3.6 Recommendation V.42 bis. British Telecom Ziv-Lempel; BTLZ: compression algorithm used in NOTE - the order of the letters “Lz” and the name “Ziv-Lempel” is not a typographical error. 3.7 the ITU-T V.24 circuits 103 (transmit data) and 104 (receive data) transfer dat
45、a at a port rate independent of the line rate. The difference in transfer rates is compensated for by buffering data as required in the modem. Neither error correction protocols nor data compression algorithms are used. For modem modulation methods which transfer data synchronously, ITU-T V. 14 sync
46、hronous/asynchronous conversion is used within the modem. buffered mode; normal mode: mode of data transmission whereby 3.8 byte: group of 8 contiguous bits; octet. 3.9 character: for bit-serial interfaces, a group of five to eight contiguous data bits that is preceded by one start (condition 2, spa
47、ce) bit and followed by at least one complete stop (condition A, mark) bit; a parity bit appearing between the final data bit and the first (or only) stop bit is optional. For bit-parallel interfaces, a character is equivalent to a byte. 4 - EIA TSB38 94 3234600 0567234 385 H TSB-38 3.10 compression
48、 mode: mode of data transmission whereby the ITU-T circuits 103 (transmit data) and 104 (receive data) transfer characters of data at a DTE port rate independent of the modem-to-modem line rate, and the transferred information is then transformed inside the modem by a compression algorithm. Informat
49、ion is transferred reliably between modems using ITU-T V.42 error control, and is compressed by using ITU-T V.42 bis compression. 3.11 the compressed data. compression ratio: ratio of the size of the original data to the size of 3.12 and a data sink. A single computer may have two DTE port and, therefore, constitute two DTEs. data terminal equipment; DTE: equipment comprising a data source 3.13 maximum number of elements in the BTLZ coding dictionary. dictionary size: V.42 bis negotiated parameter Pl that specifies the 3.14 103 (transmit data) and 104 (receive data) t
