ANSI INCITS ISO IEC 2022-1994 Information technology - Character code structure and extension techniques.pdf

1、INTERNATIONAL STANDARD ISOJIEC 2022 Fourth edition 1994-l 2-01 Information technology - Character code structure and extension techniques Technologies de /information - Structure de code de caracthres et techniques dextension Reference number ISO/IEC 2022:1994(E) Adopted by INCITS (InterNational Com

2、mittee for Information Technology Standards) as an American National Standard.Date of ANSI Approval: 1/14/99Published by American National Standards Institute,25 West 43rd Street, New York, New York 10036Copyright 2002 by Information Technology Industry Council (ITI).All rights reserved.These materi

3、als are subject to copyright claims of International Standardization Organization (ISO), InternationalElectrotechnical Commission (IEC), American National Standards Institute (ANSI), and Information Technology Industry Council(ITI). Not for resale. No part of this publication may be reproduced in an

4、y form, including an electronic retrieval system, withoutthe prior written permission of ITI. All requests pertaining to this standard should be submitted to ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaISO/IEC 2022:1994 (E) Contents Page Section 1 - General 1

5、1 Scope 1 2 Conformance 2.1 Types of conformance 2.2 Conformance of information interchange 2.3 Conformance of devices 2.3.1 Device description 2.3.2 Originating devices 2.3.3 Receiving devices 3 Normative references 4 Definitions 4.1 bit combination 4.2 byte 4.3 character 4.4 coded-character-data-e

6、lement (CC-data-element) 4.5 coded character set; code 4.6 code extension 4.7 code table 4.8 combining character 4.9 control character 4.10 control function 4.11 to designate 4.12 device 4.13 escape sequence 4.14 Final Byte 4.15 graphic character 4.16 graphic symbol 4.17 Intermediate Byte 4.18 to in

7、voke 4.19 repertoire 4.20 to represent 4.21 user 5 Notation, code tables and names 5.1 Notation 5.2 Code tables 5.3 Names of characters Section 2 - Character sets and codes 6 Characters and character sets ROIIEC 1994 All nghts reserved. No part of this publication may be reproduced or utilized in an

8、y form or by any means, electronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher ISO/IEC Copyright Office l Case Postale 56 l CH-1211 Gen b) when the code extension techniques specified in this International Standard are used, they shall be i

9、mplemented by the control functions and code-identification functions defined in this Standard with the meaning and coded representation specified in this Standard; c) no coded representation that is either reserved for registration and not assigned, or reserved for future use, shall be used; d) no

10、registered escape sequence shall be used with a meaning different from that defined by the registration. 2.3 Conformance of devices A device is in conformance with this International Standard if it conforms to the requirements of 2.3.1, and either or both of 2.3.2 and 2.3.3 below. Any claim of confo

11、rmance shall identify the document which contains the description specified in 2.3.1. 2.3.1 Device description A device that conforms to this International Standard shall be the subject of a description that a) identifies either directly, or by reference to a specification that is in accordance with

12、 this International Standard, the selection of facilities from this Standard that it can utilize when originating or when receiving CC-data-elements; b) identifies the means by which the user may supply the corresponding characters and functions, or may recognize them when they are made available to

13、 the user, as specified in 2.3.2 and 2.3.3 respectively. 2.3.2 Originating devices An originating device shall be capable of transmitting within a CC-data-element the coded representations of graphic characters from one or more graphic character sets, and of an identified selection of control functi

14、ons and code-identification functions conforming to this International Standard. Such a device shall allow the user to supply, from an appropriate set, characters or other indications which will implicitly or explicitly determine the graphic characters, control functions, and code-identification fun

15、ctions whose coded representations are to be transmitted. 2.3.3 Receiving devices A receiving device shall be capable of receiving within a CC-data-element and interpreting the coded representations of graphic characters from one or more graphic character sets, and an identified selection of control

16、 functions and code- identification functions conforming to this International Standard. Such a device shall make available to the user, from an appropriate set, characters or other indications which are implicitly or explicitly determined by the graphic characters, control functions, and code-ident

17、ification functions whose coded representations are received. 2 0 ISO/IEC ISO/IEC 2022: 1994 (E) 3 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions ind

18、icated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 maintain registers of currently valid stan

19、dards. IS0 2375:1985, Data processing - Procedure for registration of escape sequences. ISO/IEC 6429: 1992, Information technology - Controlfunctions for coded character sets. IS0 8824:1990, Information technology - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN. I

20、). IS0 8825: 1990, Information technology - Open Systems Interconnection - Specification of Basic Encoding Rules for Abstract Syntax Notation One (ASN.1). IS0 International Register of Coded Character Sets to be Used with Escape Sequences. 4 Definitions For the purposes of this International Standar

21、d, the following definitions apply. 4.1 bit combination: An ordered set of bits used for the representation of characters. 4.2 byte: A bit string that is operated upon as a unit. Note - Each bit has the value either ZERO or ONE. 4.3 character: A member of a set of elements used for the organization,

22、 control or representation of data. 4.4 coded-character-data-element (CC-data-element): An element of interchanged information that is specified to consist of a sequence of coded representations of characters, in accordance with one or more identified standards for coded character sets. Notes 1 - In

23、 a communication environment in accordance with the Reference Model for Open Systems Interconnection of IS0 7498, a CC-data-element will form all or part of the information that corresponds to the Presentation-Protocol-Data-Unit (PPDU) defined in that International Standard. 2 - When information int

24、erchange is accomplished by means of interchangeable media, a CC-data-element will form all or part of the information that corresponds to the user data, and not that recorded during formatting and initialization. 4.5 coded character set; code: A set of unambiguous rules that establishes a character

25、 set and the one-to-one relationship between the characters of the set and their bit combinations. 4.6 code extension: The techniques for the encoding of characters that are not included in the character set of a given code. 4.7 code table: A table showing the character allocated to each bit combina

26、tion in a code. 4.8 combining character: A member of an identified subset of a coded character set, intended for combination with the preceding or following graphic character, or with a sequence of combining characters preceded or followed by a non- combining character. 4.9 control character: A cont

27、rol function the coded representation of which consists of a single bit combination. 4.10 control function: An action that affects the recording, processing, transmission or interpretation of data, and that has a coded representation consisting of one or more bit combinations. 4.11 to designate: To

28、identify a set of characters that are to be represented, in some cases immediately and in others on the occurrence of a further control function, in a prescribed manner. ISO/IEC 2022:1994 (E) 8 1s0/lEc 4.12 device: A component of information processing equipment which can transmit, and/or can receiv

29、e, coded information within CC-data-elements. Note - It may be an input/output device in the conventional sense, or a process such as an application program or a gateway function. 4.13 escape sequence: A string of bit combinations that is used for control purposes in code extension procedures. The f

30、irst of these bit combinations represents the control function ESCAPE. Note -In this International Standard ESCAPE is always referred to as a control character. 4.14 Final Byte: The bit combination that terminates an escape sequence or a control sequence. 4.15 graphic character: A character, other t

31、han a control function, that has a visual representation normally handwritten, printed or displayed, and that has a coded representation consisting of one or more bit combinations. 4.16 graphic symbol: A visual representation of a graphic character or of a control function. 4.17 Intermediate Byte: A

32、 bit combination which may occur between that of the control character ESCAPE and the Final Byte in an escape sequence. 4.18 to invoke: To cause a designated set of characters to be represented by the prescribed bit combinations whenever those bit combinations occur. 4.19 repertoire: A specified set

33、 of characters that are each represented by one or more bit combinations of a coded character set. 4.20 to represent: a) To use a prescribed bit combination with the meaning of a character in a set of characters that has been designated and invoked; or b) To use an escape sequence with the meaning o

34、f an additional control function. 4.21 user: A person or other entity that invokes the services provided by a device. Notes 1 - This entity may be a process such as an application program if the “device” is a code convertor or a gateway function, for example. 2 - The characters, as supplied by the u

35、ser or made available to the user, may be in the form of codes local to the device, or of non-conventional visible representations, provided that 2.3 above is satisfied. 5 Notation, code tables and names 5.1 Notation The bits of the bit combinations of the g-bit code are identified by b, b, b, b, b,

36、 b, b, and b, where b, is the highest order, or most-significant, bit and b, is the lowest-order, or least-significant, bit. The bits of the bit combinations of the 7-bit code are identified by b, b, b, b, b, b, and b, where b, is the highest order, or most-significant, bit and b, is the lowest-orde

37、r, or least-significant, bit. The bit combinations may be interpreted to represent integers in binary notation, in the range 0 to 255 for the 4 0 1s0mx ISOAEC 2022:1994 (E) - x for the 7-bit code is the number represented by b, b, and b, where these bits are given the weights 4, 2 and 1 respectively

38、; - y is the number represented by b, b, b2 and b, where these bits are given the weights 8,4,2 and 1 respectively. The notations of the form x/y are the same as those used to identify code table positions, where x is the column number and y the row number (see 5.2). 5.2 Code tables An 8-bit code ta

39、ble consists of 256 positions arranged in 16 columns and 16 rows. The columns and rows are numbered 00 to 15 (see figure 1). A 7-bit code table consists of 128 positions arranged in 8 columns and 16 rows. The columns are numbered 00 to 07 and the rows 00 to 15 (see figure 1). The code table position

40、s are identified by notations of the form x/y, where x is the column number and y is the row number. By convention, leading zeroes are included in the column and row numbers (e.g. 02/01). The positions of the code table are in one-to-one correspondence with the bit combinations of the code. The nota

41、tion of a code table position, of the form x/y, is the same as that of the corresponding bit combination. 7-bit 5.3 Names of characters g-bit Figure 1 - Code tables This International Standard assigns one name to each character. In addition, it specifies an acronym for each control character and for

42、 the characters SPACE and DELETE. By convention, only capital letters, space and hyphen are used for writing the names of the characters. For acronyms only capital letters and digits are used. It is intended that the acronyms and this convention be retained in all translations of the text. ISO/JEC 2

43、022:1994 (E) Section 2 - Character sets and codes 0 ISO/IEC 6 Characters and character sets 6.1 Types of characters and character sets The structure of g-bit and 7-bit codes specified by this International Standard makes use of the following types of characters, character sets, and functions: - fixe

44、d coded characters, - sets of coded graphic characters, - sets of coded control functions (or control characters), - coded single additional control functions. These components are specified respectively in 6.2 to 6.5 below. The coded representations of the graphic characters and control functions a

45、re specified in relation to the g-bit and 7-bit code tables defined in 5.2 above. A coded representation for each type of component is specified within columns 00 to 07 of the g-bit and 7-bit code tables. For some components an alternative coded representation is specified in columns 08 to 15 of the

46、 g-bit code table, and is not applicable to any 7-bit code. 6.2 Fixed coded characters 6.2.1 Character DELETE Name: DELETE Acronym: DEL Coded representation: 07/15 DEL was originally used to erase or obliterate an erroneous or unwanted character in punched tape. DEL may be used for media-fill or tim

47、e-fill. DEL characters may be inserted into, or removed from, a CC-data-element without affecting its information content, but such action may affect the information layout and/or the control of equipment. 6.2.2 Character ESCAPE Same: ESCAPE Acronym: ESC Coded representation: 01/l 1 ESCAPE is a cont

48、rol character used for code extension purposes. It causes the meaning of a limited number of the bit combinations following it in a CC-data-element to be changed. These bit combinations, together with the preceding bit combination that represents the ESC character, constitute an escape sequence. Esc

49、ape sequences provide the coded representations of code-identification functions and of some types of control functions. The various uses of escape sequences are specified in clause 13. Code identification functions are specified in clauses 14 and 15. 6.2.3 Character SPACE Name: SPACE Acronym: SP Coded representation: 0200 SPACE is a graphic character. It has a visual representation consisting of the absence of a graphic symbol. It causes the active position to be advanced by one character position. 6.3 Sets of coded graphic characters 6.3.1 Types of coded graphic characte