1、 TIA-687-1997 APPROVED: SEPTEMBER 30, 1997 REAFFIRMED: NOVEMBER 20, 2001 REAFFIRMED: DECEMBER 7, 2012 TIA-687 October 1997Medium Speed Interface for Data Terminal Equipment and Data Circuit Terminating Equipment NOTICE TIA Engineering Standards and Publications are designed to serve the public inter
2、est 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 proper product for their particular need. The existence of such Standards and Pub
3、lications shall not in any respect preclude any member or non-member of TIA from 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
4、 internationally. Standards 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 Pub
5、lication. 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 safety and health practices and to determine the applicability of regulatory limit
6、ations before its use. (From Project No. 3-3416-RF2, formulated under the cognizance of the TIA TR-30.2 Subcommittee on DTE-DCE Interfaces and Protocols.) Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION Technology (b) there is no assurance that the Document will be approved by any Committee of
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19、ND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. STD-EIA TIAIb87-ENGL 1997 3234b00 058912D li89 II ANSUTINEIA-687 MEDIUM SPEED INTERFACE FOR DATA TERMINAL EQUIPMENT AND DATA CIRCUIT TERMINATING EQUIPMENT (From Standards Proposal No . 341 6 formulated under the cognizance of
20、TIA Subcommittee TR-30.2 on Data Transmission Interfaces) Contents Page 1 SCOPE . 1 I . 1 Section Abstracts 1 1.2 Application 1 1.3 Serialization 1 1.4 Synchronous/Nonsynchronous Communication 1 1.5 Classes of Service 1 2 NORMATIVE REFERENCES . 2 3 SIGNAL CHARACTERISTICS 2 3.1 Electrical Characteris
21、tics . 2 3.2 Protective Ground (Frame Ground) . 2 3.3 Shield 2 3.4 Circuit Grounding (Signal Common) 3 3.5 “Fail Safe” Operation . 3 3.6 3.6.1 Distortion . 3 3.6.2 Timing . 3 General Signal Characteristics 3 4 INTERFACE MECHANICAL CHARACTERISTICS . 5 4.1 4.2 Definition of Mechanical Interface . 5 25
22、-Position Interface Connector 5 4.3 Alt A 26-Position Interface Connector . 5 I STD-EIA TIA/b87-ENGL 1997 a 323Lib00 c1587L2L 015 m ANSITTINEIA-687 4.4 Connector Contact Assignments . 13 5 FUNCTIONAL DESCRIPTION OF INTERCHANGE CIRCUITS 14 5.1 General . 14 5.2 Classifications of Circuits 14 5.3 Defin
23、itions of Interchange Circuits . 15 5.3.1 5.3.2 5.3.3 5.3.4 5.3.5 5.3.6 5.3.7 5.3.8 5.3.9 5.3.1 O 5.3.1 1 5.3.12 5.3.13 5.3.14 5.3.1 5 5.3.16 5.3.17 5.3.18 5.3.19 5.3.20 5.3.21 5.3.22 Circuit AB . Signal Common 15 Circuit BA - Transmitted Data 15 Circuit BB - Received Data 15 Circuit CA - Request to
24、 Send 16 Circuit CB - Clear to Send . 16 Circuit CC - DCE Ready 17 Circuit CD - DTE Ready 18 Circuit CE - Ring Indicator . 18 Circuit CF - Received Line Signal Detector 18 Circuit CJ - Ready for Receiving 19 Circuit CK - Received Energy Present . 19 Circuit LL - Local Loopback . 20 Circuit RL - Remo
25、te Loopback . 20 Circuit TM - Test Mode 20 Circuit DA - Transmitter Signal Element Timing (DTE Source) 21 Circuit DB - Transmitter Signal Element Timing (DCE Source) 21 Circuit DD - Receiver Signal Element Timing (DCE Source) . 21 Circuit SBA - Secondary Transmitted Data 22 Circuit SBB - Secondary R
26、eceived Data 22 Circuit SCA - Secondary Request to Send 22 Circuit SCB - Secondary Clear to Send . 22 Circuit SCF - Secondary Received Line Signal Detector . 23 6 RECOMMENDATIONS AND EXPLANATORY NOTES 23 6 .I Line Signals 23 6.2 6.2.1 Local Loopback . 24 6.2.2 Remote Loopback . 24 6.2.3 Test Mode .
27、25 Use of Circuits for Testing . 23 6.3 Use of Circuit LL for ?Busy Out? 26 Annex A (informative) . 27 ii - STD-EIA TIAIb87-ENGL 1997 SS 3234b00 0587122 T51 ANSITTINEIA-687 FOREWORD (This foreword is not part of this Standard.) This standard was developed to provide DTEIDCE interfaces for operation
28、with unbalanced interchange circuit electrical characteristics at data rates greater than that available when using ANSITTINEIA-232-E. iii ANSITTINEIA-687 I SCOPE I .I Section Abstracts This Standard is applicable to the interconnection of data teminal equipment (DTE) and data circuit-terminating eq
29、uipment (DCE) employing serial binary data interchange with control information exchanged on separate control circuits. It defines: Section 2 Normative References Section 3 Signal Characteristics Section 4 Functional Description of Interchange Circuits In addition, the Standard includes: Section 5 R
30、ecommendations and Explanatory Notes 1.2 Application This Standard applies where equipment on one side of the DTE/DCE interface is intended for connection directly to equipment on the other side without additional technical considerations. Applications where cable termination, signal waveshaping, in
31、terconnection cable distance, and mechanical configurations of the interface must be tailored to meet specific user needs are not precluded but are beyond the scope of this Standard. I .3 Serialization This Standard applies to data communication systems where the data is bit serialized. No restricti
32、ons are placed on the sequence of bits. 1.4 SynchronousNonsynchronous Communication This Standard applies to both synchronous and nonsynchronous serial binary data communications systems. 1.5 Classes of Service This Standard applies to switched, nonswitched, dedicated, leased or private line service
33、. Consideration is given to both point-to-point and multipoint operation. 2 NORMATIVE REFERENCES The following standards contain provisions which, through reference in this text, constitute provisions of this Standard. At the time of publication, the editions indicated were valid. All standards are
34、subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards 1 ANSITTINEIA-687 indicated below. ANSI and TIA maintain registers of currently valid national standards published by them. ANSITT
35、INEIA-334-B Signal Quality at Interface Between Data Terminal Equipment and Synchronous Data Circuit- Terminating Equipment for Serial Data Transmission ANSITTINEIA-404-B standard for Start-Stop Signal Qualify for Non-Synchronous Data Terminal Equipment ANSITTINEIA-423-B Electrical Characteristics o
36、f Unbalanced Voltage Digital Interface Circuits 3 SIGNAL CHARACTERISTICS 3.1 Electrical Characteristics The electrical characteristic of the interchange circuits are specified in ANSITTINEIA-423-B. The meaning of circuit conditions “ON” and “OFF” for control and timing circuits, and “O”, “I”, “MARK”
37、, and “SPACE” for data circuits, shall be as defined in ANSITTINEIA-423-B. 3.2 Protective Ground (Frame Ground) In DTEs and in DCEs, protective ground is a point that is electrically bonded to the equipment frame. It may also be connected to external grounds (e.g., through the third wire of the powe
38、r cord). It should be noted that protective ground (frame ground) is not an interchange circuit in this Standard. If bonding of the equipment frames of the DCE and the DTE is necessary, a separate conductor should be used that conforms to the appropriate national or local regulation applying to wire
39、 size and color coding. 3.3 Shield In order to facilitate the use of shielded interconnecting cable, interface connector contact number 1 is assigned for this purpose. This will permit the cable associated with the DTE to be composed of tandem connectorized sections with continuity of the shield acc
40、omplished by connection through this contact in the connectors. Normally the DCE should make no connection to interface connector contact number 1. It is recognized that for certain electromagnetic interference (EMI) suppression situations, additional provisions may be necessary but are beyond the s
41、cope of this Standard. 3.4 Circuit Grounding (Signal Common) Proper operation of the interchange circuits requires the presence of a path between the DTE circuit common and the DCE circuit common. This path is obtained by means of two interchange Circuits AB, Signal Commons. Both the DCE and the DTE
42、 normally should have 2 STD-EIA TIA/b87-ENGL L997 = 3234b00 05891125 7b0 ANSITTINEIA-687 their circuit common connected to their protective ground through a resistance of 100 ohms (120%) having a power dissipation rating of one-half watt. Figure I illustrates the signal common and grounding arrangem
43、ent. 3.5 “Fail Safe” Operation The receivers of the following interchange circuits: Circuit CC (DCE Ready) Circuit CA (Request to Send) Circuit CD (DTE Ready) shall be used to detect a power-off condition in the equipment connected across the interface and the disconnection of the interconnection ca
44、ble. Detection of either of these conditions shall be interpreted as an OFF condition of the interchange circuit. 3.6 General Signai Characteristics 3.6.1 Distortion Interchange circuits transferring data signals across the interface point shall hold the marking (binary ONE) and spacing (binary ZERO
45、) conditions for the total nominal duration of each signal element. Distortion tolerances for synchronous systems are set forth in TINEIA-334-B. tolerances for nonsynchronous systems are set forth in TIAIEIA-404-B. Distortion 3.6.2 Timing Interchange circuits transferring timing signals across the i
46、nterface point shall hold ON and OFF conditions for nominally equal periods of time consistent with acceptable tolerances as specified in TINEIA-334-B. Accuracy and stability of the timing information on Circuit DD (Receiver Signal Element Timing) is required only when Circuit CF (Received Line Sign
47、al Detector) is in the ON condition. Drift during the OFF condition of Circuit CF is acceptable: however, resynchronization of the timing information on Circuit DD must be accomplished as rapidly as possible following the OFF to ON transition of Circuit CF. it is desirable that the transfer of timin
48、g information across the interface be provided during all times that the timing source is capable of generating this information (.e., it should not be restricted only to periods when actual transmission of data is in progress). During periods when timing information is not provided on a timing inte
49、rchange circuit, the interchange circuit shall be clamped in the OFF condition. Tolerances on the relationship between data and associated timing signals shall be in accordance with TINEIA-334-B. 3 ANSI/TIA/EIA-687 Note 1 : Note 2: GWG is green wire ground of power system Normally no connection to shield in DCE (see 2.3) Figure I - Signal Common and Grounding Arrangement 4 STD-EIA TIA/b87-ENGL 1777 E 3234b00 0587327 533 Sll ANSITTINEIA-687 4 INTERFACE MECHANICAL CHARACTERISTICS 4.1 Definition of Mechanical Interface The point of demarcation between the DTE and the DCE
