1、TIA/EIA STANDARD ANSI/ TIA/EIA-617-1995 Approved: July 10, 1995 Data Transmission Systems and Equipment In-Band DCE Control TIMIA-617 JANUARY 19% TELECOMMUNICATIONS INDUSTRY ASSOCIATION EIA TIA-bL7 76 1111 3234600 0568707 207 m NOTICE TIA/EIA Engineering Standards and Publications are designed to se
2、rve the public interest through eliminatllig 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 his particular need. Existence of such St
3、andards and Publications shall not in any respect preclude any member or nonmember of TIA/EIA fiom manufacturing or selling products not conforming to such Standards and Publications, nor shaU the existence of such Standards and Publications preclude their voluntary use by those other than TIA/EIA m
4、embers, whether the standard is to be used either domestically or internationally. Standards and Publications are adopted by TIAEIA in accordance with the Amencan National Standards Institute (ANSI) patent policy. By such action, TIA/EIA does not assume any liability to any patent owner, nor does it
5、 assume any obligation whatever to parties adopting the Standard or hblication. This Standard does not purport to address ail safe problems associated with its use or all applicable regulatosr requirements. It is the responsibility of the user of this Standard to establish appropriate safety and hea
6、th practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposai Nos. 2812-A and 2812-A-1, formulated under the cognizance of the TR- 30.4 Subcommittee on DTE-DCE Protocols.) Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1996 Standards and Te
7、chnology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to current or cail Globai Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) Catalog of EIA, JEDEC, and TIA STANDARDS and ENGINEERING PUBLICATIONS Ail rights reserved Printed in U.S.A.
8、EIA TIA-bL7 96 U 3234600 056708 145 PLEASE! DONT VIOLATE THE LAW! This document is copyrighted by the TIA and may not be reproduced without permission. Organizations may obtain permission to reproduce a Limited number of copies through entering into a license agreement. For information, contact: Glo
9、bal Engineerhg Documents 15 Inverness Way East Englewood, CO 801 12-5704 or call U.S.A. and Canada 1-800-854-7179, International (303) 397-7956 EIA TIA-bL7 76 BI 3234600 05bflC109 O1 I ANSI/TIA/EIA-617 Data Transmission Systems and Equipment In-Band DCE Control Contents 1 SCOPE . 1 2 NORMATIVE REFER
10、ENCES 2 3 DEFINITIONS . 3 4 PHYSICAL LAYER . 5 4.1 NECESSARY SERIAL INTERFACE CIRCUITS 5 4.2 REPRESENTED CIRCUITS 5 4.3 NON-SERIAL CIRCUITS . 5 5 SERIAL PORT CONSIDERATIONS . 6 5.1 SERIAL PORT RATE 6 5.2 SERIAL PORT RATE WHEN USED IN COMMAND STATE 6 5.3 FLOW CONTROL INTERACTIONS . 6 5.4 DATA STREAM
11、ERRORS 6 6 IN-BAND CONTROL PROCEDURES . 6 6.1 BASIC MODE TRANSPARENCY . 7 6.1.1 Character Set . 7 6.1.2 In-Band Escape Character 7 6.1.3 Basic In-Band Command Structure . 7 6.1.4 Extended ln-Band Command Structure 8 6.1.5 In Data . 8 6.1.6 Invalid In-Band Command Recovery 8 6.2 IN-BAND COMMAND EXECU
12、TION 8 - 6.3 DTE-TO-DCE DATA STR EAhAs . 8 6.4 DCE-TO-DTE DATA STREAMS . 9 6.5 DCE STATUS REPORTING TO THE DTE 9 6.6 DTE STATUS REPORTING TO THE DCE 9 7 IN-BAND COMMAND DEFINITIONS 9 7.1 IN-BAND COMMANDS SENT BY THE DTE TO DCE 10 7.2 IN-BAND COMMANDS SENT BY THE DCE TO DTE 11 7.3 EXTENDED IN-BAND CO
13、MMANDS SENT FROM DTE TO DCE 12 7.3.1 BREAK Command 13 7.3.2 MARK Idle Command . 13 7.3.3 CONTROL Extended In-Band Command . 13 7.4.1 BREAK Command 15 7.4.2 MARK Idle Command . 15 7.4.3 STATUS Report Extended In-Band Command . 15 7.4 EXTENDED IN-BAND COMMANDS SENT FROM DCE TO DTE 14 8 IN-BAND SERVICE
14、 CONTROL 6 8.1 OVERALL SERVICE CONTROL . 16 8.2 INDIVIDUAL STATUS CONTROL . 16 8.3 TINEIA-615 FORMATED SYNTAX FOR CONTROL OF IN-BAND CONTROL 16 8.3.1 Set the In-Band Service Controls, +IBC= 16 8.3.2 Read the Current in-Band Service Settings, +IBC? . 17 i EIA TIA-bL7 96 E 3234600 0568730 T3 E TIA/EIA
15、-617 8.3.3 Test the Current in-Band Service Settings. +iBC=? 17 8.3.4 Subparameter Definitions . 17 8.4 IN-BAND MARK IDLE REPORTING CONTROL. +IBM 18 8.4.1 Mark idle Period Intervals . 18 8.4.2 Set Mark-Idle Report Controls 18 8.4.3 Read the Current In-Band Service Settings. +IBC? . 19 8.4.4 Test the
16、 Current In-Band Service Settings. +IBC=? 19 ii (This foreword is not part of this Standard.) Foreword This standard was prepared by TIA TR-30.4, DTE-DCE Protocols. This is the first approved version of this standard. TIA TR-45.5 has contributed to this Standard. iii EIA TIA-617 96 3234600 05613912
17、676 = TIAIEIA-617 1 Scope Standards exist for DTE Control of DCE using Serial Data Interchange and Start-Stop framing (TIAIEIA-602, CCIlT V.25bis). When user data is not being transferred, DTE commands and DCE responses are delivered on the same data paths used for user data, such as V.24 circuits 1
18、03 and 1 04. The above mentioned Standards use out-of-band mechanisms for control while user data is being transferred, such as V.24 circuits 108/2 and 1 O9 for call control and status, and circuits 133 and 106 for flow control. All commands or status messages delivered on circuits 103 and 104 must
19、be applied while user data transfer is suspended or terminated. This Standard describes procedures for a DTE and DCE to exchange control and status using only the data transfer path. There is need for In-Band mechanism for DCE control, because Out- of-band mechanisms are not available on all DTE, du
20、e to interface restrictions or DTE system software. These procedures depend on the integrity of the data transfer path. It is preferred that the DTE- DCE link should provide some means to prevent loss-of-data errors or other corruption of In- Band control information. The specification of means to p
21、revent loss-of-data is beyond the scope of this standard. These procedures must be time-independent because inter-character delay time cannot be preserved in DTE containing multi-tasking software, large character buffers or intermediate data links (e.g., Local Area Networks). This standard defines a
22、daptation of Basic Mode Control Procedures from IS0 Standard 21 11 for time-invariant In-Band signaling of the following functions: - a) Define a mechanism for in-band delivery of control and status information between DCE and DTE b) Represent V.24 circuits using transparent In-Band Commands. c) Pol
23、l the corresponding device for its V.24 circuit status. Using these mechanisms, these In-Band Commands may be used to provide: d) e) 9 9) h) i) In-Band commands for Flow control (circuits 106 and 133) Data stream termination (circuit 108/2 w/AT otherwise, it is a short command. Except for the escape
24、 character, all short or extended command characters are limited to the range of 20h to 7Eh. In-Band Control Circuit: a logical circuit defined between DTE and DCE, but which is presented by one device to the other by means of In-Band Commands instead of (or in addition to) by means of physical out-
25、of-band circuits. 3 EIA TIA-617 96 W 3234600 0568935 385 TIA/EIA-617 Hexadecimal coding: In this standard, hexadecimal coding is used. Hexadecimal is base-16, with the first six letters of the Roman alphabet (A-F) used to represent the digit values 10 - 15, in addition to the numerals 0-9 used for t
26、heir traditional digit values. A single hexadecimal digit represents a four-bit binary number; two consecutive hexadecimal digits represents an 8-bit number, with the first digit representing the 4 most significant bits, and the second digit representing the 4 least significant bits. In this standar
27、d, two hexadecimal digits are followed by the lower case “h“ to indicated hexadecimal notation. For example, 5Dh represents 0101 11 O1 in binary, or 93 in decimal, or 5/13 in ITU-T (CCllT) T.50 character notation. Break: extended periods of constant logic-zero on V.24 circuit 103 or circuit 104. Mar
28、k Idle: extended periods of constant logic-one on V.24 circuit 103 or circuit 104. EIA TIA-bL7 96 ILI 3234b00 0568936 211 TIAIEIA-617 4 Physical Layer Procedures defined in this standard are useful on interfaces based on bit-serial data interchange, and on other digital interfaces. This standard is
29、referenced to standard bit-serial interfaces; examples include ITU-T (CCirr) V.24, EIA/TIA-232-E, EIA/TIA-530-A, EIA/TIA-561, EIAITIA- 574. For other interfaces (e.g., IEEE 1284), a bi-directional character-serial channel is required. 4.1 Necessary Serial Interface Circuits For standard serial inter
30、faces, the following circuits are intercepted and controlled by the DCF. The DCF is designed so that it will function properly if only these circuits are connected or implemented. Circuit Description 102 Signal Common - Connection of this circuit is required for proper recognition of signals on othe
31、r circuits. (Note: this is needed for electrical interchange; it is not needed for InfraRed or other wireless interfaces.) Transmitted Data - While in the command state, data signals are processed by the DCF and not transmitted to the remote station. In Data State, data signals are processed to dete
32、ct In-Band Commands; otherwise, data signals are passed to signal converters and optional error control functions. 103 104 Received Data - While in the command state, data received from the remote station is buffered or ignored, and the DCF delivers responses to the DTE on this circuit. In data stat
33、e, the DCE may deliver In-Band Commands to the DTE, if enabled by the DTE. 4.2 Represented Circuits The following CCIlT V.24 physical circuits may be represented by In-Band character sequences described in this Standard. When so configured, the In-Band circuit shall be used by the receiving device i
34、n place of the corresponding physical circuit. It is preferred that the sending device should present the same information on the physical circuit as it presents on the in-Band circuit, if these physical circuits are available. 105 Request to send 106 Ready for sending 107 Data set ready 108/2 Data
35、terminal ready 1 O9 125 Calling indicator 133 Ready for receiving Data channel received line signal detector 4.3 Non-Serial Circuits For non-standard interfaces, there shall be a means to send and receive data simuhaneoudy between the DCE and DTE. In the case where the circuit between the DCE and DT
36、E invoive networks or other systems which can be represented by the IS0 Network Model, In-Band Command implementations shall be a Presentation Layer service. 5 5 Serial Port Considerations 5.1 Serial Port Rate The procedures defined in this standard may be used at any bit-serial port rate supported
37、by DTE and DCE. However, for any In-Band Command, the serial port rate shall be fixed. Means to determine the serial port rate is beyond the scope of this standard. 5.2 Serial Port Rate when used in Command State Section 4.3rTINEIA-602 describes a DCE which can automatically detect the serial pori r
38、ate for new command lines during Command State: this is called autobauding. If operating in Command State, the DTE shall send In-Band commands at the same serial port rate used in the most recently received valid command line. In-Band command shall not be embedded between the leading “A (41 h) or “a
39、“ (61 h) command line prefix character and the next subsequent character in the command line prefix, e.g., “T“ (54h), “t“ (74h) or I/“ (2Fh). The DCE must be capable of detecting In-Band commands in addition to new command lines. If operating in Command State, the DCE shall send In-Band commands at
40、the same serial pori rate used in the most recently received valid command line. The DTE must be capable of detecting In-Band commands in addition to other DCE responses. Note: it is assumed that the DTE defaults with In-Band Commands disabled, so that an AT command is needed to enable In-Band Comma
41、nds; that AT command will set the default serial port rate thereafter. 5.3 Flow Control Interactions There are several different mechanisms defined for flow control in asynchronous DCE. The definition of these means is beyond the scope of this standard. If the procedures defined in this standard are
42、 enabled to represent the standard serial interface flow control circuits (106 and 133), and if the DCE is configured for 106/133 flow control, then these In-Band control circuits could be used for flow control. 5.4 Data Stream Errors On serial interchange data circuits (103 and 104) In-Band command
43、s are subject to the same errors as bearer data. Corruption or loss-of-data has serious adverse consequences, since the control information is presented as a transient string rather than as a static physical circuit. Corrupted In-Band Commands will be lost; corrupted data can result in erroneous det
44、ection of In- Band commands. In either case, communications system failure is a probable result. If the DTE-DCE interface is subject to errors, provisions should be made to ensure reliable system operation. For example DTE or DCE may send repeated In-Band commands to represent a static circuit condi
45、tion, to increase chances of successful detection. A data link protocol could also be used, such as TINEIA-605. 6 6 In-Band Control Procedures In common DCE with ACE (TINEIA-602, CCIlT V.25bis) the DCE expects commands from the DTE only while in a defined command state. DCE conforming to this standa
46、rd include the ability to recognize and accept DTE commands which are embedded in user data delivered on V.24 circuit 103, and include the ability to generate DCE commands and status messages to the DTE, embedded in user data on V.24 circuit 104. These features are controlled by a DTE command, defin
47、ed in section 8 of this standard. The procedure defined in this standard for representing these In-Band Commands is based on Basic Mode Transparency, defined in IS0 Recommendation 21 11. 6.1 Basic Mode Transparency 6.1.1 Character Set The character set used to build valid In-Band Commands is the set
48、: 20h - 7Eh AOh - FEh 7 or 8 bit characters 8 bit characters The most significant bit (Z7) is ignored. 6.1.2 In-Band Escape Character The flag character for In-Band commands is the ASCII EM character, which has an ordinal value of 19h. The 8th bit (bit Z7) may be zero or one and is ignored. NOTES 1
49、- In 8-bit systems, the flag character may have the value of 19h (odd, mark, masked, or no parity) or 99h (even or space parity). 2 - Throughout the remainder of this document, the flag character is denoted mnemonically as 6.1.3 Basic In-Band Command Structure Basic In-Band Commands consist of .CEM and a single valid command character. Tables 1 and 2 list defined Basic In-Band Commands. 6.1.4 Extended In-Band Command Structure Extended In-Band Commands consist of: 0 0 0 a valid length byte a valid command character defined as an extend command (see tables 1 and 2), 1 to 95 addit
