CEN Guide to the Use of Character Sets in EuropeTC 304

8-bit Character Sets - ISO/IEC 2022

Current edition

ISO/IEC 2022:1994
Information technology - Character code structure and extension techniques (fourth edition).


This standard specifies a structure for 7-bit and 8-bit codes that is adopted by all such codes produced under the auspices of ISO/IEC JTC1/SC2. This is the subcommittee entrusted jointly by ISO and IEC with the development of character set coding matters.

This standard also specifies means by which the correspondence between bit combinations and characters may be changed during a particular instance of information interchange. This is known as code extension. It makes use of control functions that are themselves represented by bit combinations within the original code.

Tutorial guidance

This guide contains introductions to the features of ISO/IEC 2022 at various levels:

The facilities of ISO/IEC 2022 are of a powerful and general nature. A simplified structure for 8-bit codes and code extension is specified in ISO/IEC 4873. The structure of ISO/IEC 4873 does not permit multiple-byte coded character sets to be invoked and therefore excludes, for example, the coding of Japanese, Chinese and Korean ideographic characters as described in the section of this guide on graphic characters.

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