ISO/IEC TECHNICAL REPORT TR 9789 First edition 1994-12-15 Information technology ---- Guidelines for the organization and representation of data elements for data interchange Coding methods and principles Technologies de I'information - Principes directeurs pour I'organisation et la representation des élements de donnees pour I'échange de données - Méthodes et principes de codage IEC Tso Reference number ISO/IEC TR 9789:1994(E) Copyright Intemational Organization for Standardization oyIHS Not for Resale ISO/IECTR9789:1994(E) Contents Scope 1 1 2 References 11 2.1 General references 2.2 Examples of applications of this Technical Report 1 3 Definitions 2 4. Principles of coding . 3 4.1 Information and coding 3 4.2 Coding 4 5 Coding objectives . 456 5.1 Identification 5.2 classification 5.3 Key to further prmation 6 6 Types of codes 7 6.1 Forms of codes 7 6.2 Sequential codes 7 6.3 Random codes 10 6.4 Mnemonic codes 11 6.5 Abbreviation based codes 12 6.6 Matrix codes 13 6.7 Hierarchical codes 14 6.8 Juxtaposition codes 15 6.9 Combination codes 16 6.1oValue addition code 16 7 Features of codes 17 7.1 General 17 7.2 Uniqueness 17 7.3 Expandibility 18 7.4 Conciseness 18 7.5 Simplicity 18 7.6 Versatility 18 7.7 Suitability for sorting 18 7.8 Stability 18 7.9 significance 19 7.10Size 19 7.11 Structure and format 20 7.12Capacity 20 Representation of code values 21 8 21 8.1 character sets 8.2 Representation techniques 22 ISO/IEC1994 All rights reserved. Unless otherwise specified, 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 Switzerland ii yright Intemational Orga zation for Standardization ISO/IECTR9789:1994(E) @ISO/EC 9 Design codes 23 of 9.1 23 General 9.2 Number of 24 9.3 Format of the coded representation 25 Character sets. 26 9.4 9.5 Assignment conventions 9.6 Error detection by using check characters application 28 9.7 Recommendations for some areas 28 9.8 Practical recommendations ili Copyright Intemational Organization for Standardization Not for Resale