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1、STD-JIS X 5002-ENGL 1975 4933b08 054198b 082 W JIS UDC 681 .322.078 JAPANESE IN DUSTRIAL STANDARD Basic Mode Data Transmission Control Procedures JIS C 6 3 6 2 - 1 9 7 5 The code number of this standard JIS C 6362 changed to the follow- ingon 1 March 1987. JIS X 5002-1975 Translated and Published by
2、 Japanese Standards Association Printed in Japan 18 S In the event of any doubt arising, the original Standard in Japanese is to be final authority. -,-,- STD-JIS X 5002-ENGL 3775 4733b08 0543788 755 M UDC 681.322.078 JAPANESE INDUSTRIAL STANDARD J I S Basic Mode Data Transmission Control Procedure6
3、 X 5002-1975 (Reaffirmed: 1994) 1. General 1.1 Scope This Japanese Industrial Standard specifies control procedures of data transmission using transmission control characters, which are specified by JIS X 0201, through data transmission lines between data terminal or data processing equipments. 1.2
4、General Principle Concerning Specification The general principle con- cerning specification is as described below. (1) This standard does not specify anything concerning hardware and soft- ware to implement the transmission control procedures. (2) This standard does not specify anything concerning t
5、ransmission methods, synchronization methods, and data signalling rates which are used when the transmission control procedures are applied. (3) Either the same or different channels may be used to send responses of message or forward supervisory sequences. (4) The transmission control procedures sp
6、ecify not only one- way transfer and alternate two-way transfer of information based upon the control by alternate supervision but also two-way simultaneous transfer with alternate supervision. 2. Definitions For the purpose of this standard the following principal definitions, in addition to those
7、specified i n JIS X 0001, shall apply: (1) message A set of data designed for transmission of information with The message consists of characters or a well specified head and tail. a character sequence which include at least one transmission control character. (2) information message A set of data w
8、hich is the primary object of data The information message consists of a text which may be transmission. preceded by a heading. (3) station General term for an equipment which is connected to a data communication network and conducts data transmission, reception , or processing, and for the place wh
9、ere the equipment is located. (4) master station The station which has, at an instant, the right to send an information message to slave stations and has the responsibility to faithfully execute the transfer of information. Applicable Standards: JIS X 0201- Code for Information Interchange JIS X 000
10、1-Glossary of Terms Used in Information Processing JIS X 5001-Character Structure on the Transmission Circuits and Horizontal Parity Method JIS X 5101-The Interface between Date Circuit Terminating Equipment (DCE) and Data Terminal Equipment (DTE) (25-pin Interface) -,-,- STD-JIS X 5002-ENGL 1975 i7
11、33b08 0543787 871 W 2 C 6362-1975 slave station an information message from a master station. The station which is, at an instant, capable of receiving control station ditions of all stations connected to the system, supervises those stations, or controls abnormal condition for its recovery. The sta
12、tion which controls message transmission con- tributary station station. Any station of the system which is not the control forward direction control station to a tributary station prior to establishment of a data link; direction of the transmission of a message from a master station to a slave stat
13、ion after establishment of a data link. Direction of the transmission of a message from a backward direction rhes connecting two stations without branching stations between them. This system does not have a control station. The system with a single data processing center so-called the radial type ne
14、twork-structure system is included in this standard. Direction opposite to the forward direction. oint-to-point system A data communication system with communication block ofaracter sequences, and which is preceded or followed by at least one transmission control character. A division of an informat
15、ion message which consists of a group block check mission. A method of detecting errors introduced during data trans- In this method, information is examined block by block. initial status of the data link. Status of a point-to-point system prior to establishment control status system with a control
16、 station prior to establishment of a data link. Status of a network-structured data communication data link mitting equipment to a receiving equipment through a transmission line and for a logical path of data transfer. General term for a physical transmission path from a trans- code independent The
17、 notion that codes to be transmitted to convey an information message are free from restrictions required by different kinds of lines and data transmission control procedures. alternate supervision A type of transmission in which blocks or for- ward supervisory sequences are transmitted not continuo
18、usly but in an alternating fashion with backward supervisory sequences such as res- pons of message. time fiil maintain synchronization or to provide some delay time. A set of idle codes placed between blocks or characters to recovery transmitting and receiving equipments or communication channels.
19、To break a deadlock condition caused by malfunctions of -,-,- STD-JIS X 5002-ENGL 1975 4933b08 0543970 503 3 C 6362-1975 (20) octet An information transfer unit which consists of bit sequence of &bits. 3. Basic Modes 3.1 Message Structure 3.1.1 General Rules General rules concerning the message stru
20、cture are as follows: (i) Any message to be transmitted is expressed in characters or character sequences and is categorized into the following three groups: (a) Information message (b) Forward supervisory sequence (c) Backward supervisory sequence Each message shall include at least one transmissio
21、n control character to specify characteristics of the information in the message, or to perform its supervising function. The transmission control characters shall not be treated as inform- ation. text of the information message nor as content of the heading. How- ever , SYN , which is inserted and
22、transmitted when necessary is the only exception , although - SYN does not carry information. In other words, they shall not be transmitted as a part of the When a single or combined transmission control characters are used at the end of the message, their receiving station is invited to initiate so
23、me action. 3.1.2 Structure of Information Message Structure of information message is described below. Information message consists of a text or a text and a heading which precedes the text. Heading is the one which is attached to each text if necessary. Designation of transfer line, particularly th
24、e one at a relay point in the store-and-forward switching network, shall be included in the heading. the heading or the text. Other supplementary information may be included in either Each of the characters SOH, STX, ETB, and ETX - is used for framing information messages. - These characters alone a
25、re not transmitted. Information message or a block may be accompanied by a block check character (BCC) or a block check sequence (BCS). check calls for an agreement in advance between the transmitting and receiving ends. The use of block Structure of an information message or a block is specified be
26、low. Transfer may begin with any of structures (a) to (e). However , the structure of the one to be transferred finally shall be (d) or (e). -,-,- STD-JIS X 5002-ENGL 1775 Y733bO 0541791 L(YT M 4 C 6362-1975 (a) SOH - heading - ETB (BCC) - (b) SOH - heading - STX - text - ETB - (BCC) (c) STX - text
27、- ETB - (BCC) SOH - heading - STX - text - ETX - (BCC) - (e) STX - text - ETX (BCC) Remarks 1 . 2. - SYN may be embedded in the heading or text if necessary. Structure of the information message in case of transfer abort is specified in 3.6.1. 3. (BCC) may be replaced by (BCS). 3.1.3 Supervisory Seq
28、uences The structure and use of supervisory sequences are described below. Except for the supervisory sequence with DLE, each supervisory sequence consists of one transmission contxcharacter or the one with a prepositioned character sequence preceding the character. If highly reliable transmission i
29、s required, transmission control characters which are specified to be transferred as a single character may be repeated and combined into two characters to be transferred consecutively upon an agreement between the transmitting and receiving ends. A prepositioned character sequence shall be expresse
30、d in the graphic characters specified in JIS X 0201 and its length shall be equal to or less than 15 characters. The prepositioned character sequence contains, in addition to a poll- ing address for polling and a selecting address for selecting, the following information based upon a prior agreement
31、 between the trans- mitting and receiving ends. (a) Recognition information (b) Address information (c) Status information (d) Other necessary information These kinds of information are termed prefixes. The use of a pre- fix is optional. The kinds and structure of basic forward supervisory sequences
32、 are listed i n Table 1. sub-clauses 3.2 to 3.7. (5) The use of each sequence is specified in each of STD-JIS X 5002-ENGL 1975 = Li733b08 05LiL772 38b W Termination Abnormal termination Clearing of connection 5 C 6362-1975 EOT DLE - EOT - - - Table 1. Kinds of Forward Supervisory Sequences Block abo
33、rt Abort Polling (Prefix) ENQ I (EOT) - polling address - ENQ - Selecting St at ion selection (EOT) - selecting address -ENQ l- Recognition or status request (Prefix) ENQ Escape from initial status (Prefix) ENQ Regular termination (Prefix) EOT - information message response request I (Prefix) ENQ I
34、EOT - Station abort Remark: EOT precedes a polling sequence except for the one i n which Em - is unnecessary in the light of the function of the phase 1. EOT may also precede a selecting sequence. (6) The kinds and structure of basic backward supervisory sequences are listed in Table 2. of sub-claus
35、es 3.2 to 3.7. The use of each sequence is specified each -,-,- STD-JIS X 5002-ENGL 1975 m 4733b08 05q1773 212 m Kinds 6 C 6362-1975 S truc t Ure Selection reply Positive acknowledge ACK - (Prefix) Information message I reply ACK - (Prefix) Polling reply Negative acknowledge EOT - (Prefix) (Prefix)
36、I Negative selection Negative information message reply NAK (Prefix) Block interrupt Stat ion interrupt NAK EOT DLE - I-Invaii, 1 1L - (timeout) I procedures I I 7 Other recovery No answer Recovery procedure (R3) L - - n3 times of triais - Slave station Master station (1) Block Abort (see Fig. 5) Th
37、e block abort procedure is initiated by the master station when it is necessary for the master station to stop the transfer, without having the data link returned to the control status or the initial status, before terminating the block normally (with an ETB or ETX) . When the master station calls f
38、or block abort, the station terminates the transfer of the block by immediately sending (Prefix) ENQ. - - In this case, the slave station returns a negative acknowledge. The negative acknowledge is the only valid reply in this case. the reply from the slave station is invalid or null, the recovery p
39、rocedure (R3) specified in 3.7.3 applies. If Then, if necessary, the master station resumes the transfer of a block preceded by an STX (or SOH). - Fig. 5. Block Abort (2) Station Abort (see Figs. 6 and 7) (a) The master station initiates this procedure when the station calls , for stop of data trans
40、fer during the transfer, to change the status to the control or Uiitial status. (b) When the master station calls for station abort in the middle of a block, the station first executes the block abort procedure and then sends an EOT to return data link to the control or initial status. -,-,- STD*JIS
41、 X 5002-ENGL 1975 m Li733b08 0592005 b32 m - - n , times of trials Slave station Master station- - 18 C 6362-1975 / Master station F - When the master station conducts station abort between two blocks, the station finishes the block being transferred i n a normal mode. The normal reply of this block
42、 from the slave station is the positive acknowledge. Then the master station sends an EOT - to return the communication link to the control or initial status. Whether a re- covery procedure applies when a negative or invalid acknowledge is received depends upon an agreement between the transmitting
43、and receiving ends. In the switching lines, the EOT - may be replaced by - DLE EOT . Fig. 6. Station Abort (While a Block is being Sent) Fig. 7. Master Station Abort (Betweer1 Two Information Blocks) -,-,- STD-JIS X 5002-ENGL 1975 = 9933b08 059200b 579 W 19 C 6362-1975 3.6.2 Interrupt When the slave
44、 station calls for end or stop of the trans- mission by the master station during the reception of information message, the transmission is terminated in accordance with the block interrupt procedure or the station interrupt procedure which is described below. (1) Block Interruption (see Fig. 8) (a)
45、 The slave station initiates the block interrupt procedure when the slave station is for some reason no longer capable of continuing the reception, at the end of an information message or block, and desires for the master station to immediately end the data transfer. (b) The slave station sends an E
46、OT instead of a normal reply. The EOT L_ designates negative acknowledgement of the block received finally and ends the transmission at that time. to the control or initial status. - Data link returns (c) The block break procedure does not apply to the system with a control station in which communic
47、ation is done between the tributary stations i n the non-centralized method. (2) Station Interrupt (see Fig. 9) (a) The slave station initiates the station interrupt procedure when the slave station requests the master station to immediately stop the data transfer. (b) Station interrupt is done by t
48、ransferring a DLE - sequence specified in 3.1.3 instead of using a normal positive acknowledge. (c) This reply possesses the following two functions: (i) A positive acknowledge of the received block or selecting sequence. (U) A request for immediate termination of the transmission. (d) The moment when the master station practically ends the transmis- sion may be determined by each system. -,-,- STD-JIS X 5002-ENGL 1975 4733b08 0542007 405 20 C 6362-1975 Fig. 8. Block Interrupt (Text /heading) I 0 Control status (or -_ Master stat