ISO/IEC INTERNATIONAL STANDARD 646 Third edition 1991-12-15 Information technology -- IsO 7-bit coded character set for information interchange Technologies de I'information -- Jeu iso de caracteres codes a 7 elements pour I'échange d'informations Reference number ISO/IEC 646:1991(E) Copyright International Organization for Standardization etworking permitted without license from IHS Not for Resale ISO/IEC 646:1991 (E) Contents Page 1 1 Scope 1 2 Conformance and implementation 1 2.1 Conformance 1 2.1.1 Conformance of information interchange 1 2.1.2 Conformance of devices 2 2.2 Implementation 2 3 Normative references 2 4 Definitions 2 4.1 active position 2 4.2 bit combination 2 4.3 character 2 4.4 character position 2 4.5 coded character set 3 4.6 coded-character-data-element (CC-data-element) 3 4.7 code extension 3 4.8 code table 3 4.9 control character 3 4.10 control function 3 4.11 device 3 4.12 escape sequence 3 4.13 Final Byte 3 4.14 graphic character 3 5 graphic symbol 4.15 3 4.16 repertoire 3 4.17 user 3 Notation, code table and names 5 3 5.1 Notation 4 5.2 Code table 4 5.3 Names 4 6 Specification of the coded character set 4 6.1 Structure 5 6.2 Control characters @ ISO/IEC 1991 Allrights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. ISO/IEC Copyright Office · Case postale 56 . CH-1211 Geneve 20 : Switzerland Printed in Switzerdand ii CopyrihtInternatioal Organization for Standardizatin tworking permited without license from IHS Not for Resale ISO/IEC 646:1991 (E) 6.3 Character SPACE 5 5 6.4 Graphic characters 6.4.1 Unique graphic character allocations 5 7 6.4.2 Alternative graphic character allocations 8 6.4.3 National or application-oriented graphic character allocations 5 Character DELETE 8 6.5 7 Composite graphic characters 8 8 8 Versions of the coded character set Genera! 8 8.1 International Reference Version (IRV) 6 8.2 9 8.3 National versions 8.4 Application-oriented versions 10 9 Identification of versions 10 10 9.1 Purpose and context of identification 9.2 Identification of a version 10 Explanation of Code tables No. 4 and No. 5 10 10 Annexes 13 Specification of the CO set A Guidelines for standards derived from ISO/IEC 646 14 B Differences between the second edition (1983) and the present (third) edition of this International C Standard 15 ii CopyrhtInternatinalOrganizationfor Standardization ited without license from IHS Not for Resale