CEN Guide to the Use of Character Sets in EuropeTC 304

8-bit Character Sets - ISO/IEC ISP 12070

Current edition

ISO/IEC ISP 12070-1:1996
Information technology - International Standardized Profiles FCSnnn - Character Set - Code Structure based on ISO/IEC 2022 - Part 1: FCS111 - 2022 Option 1 (first edition).


The profile ISO/IEC ISP 12070 forms part of the documentation of Open Systems Interconnection (OSI), for which the Basic Reference Model is specified in ISO/IEC 7498-1:1994 (second edition).

The profile ISO/IEC ISP 12070 was planned as an International Standardized Profile in multiple parts. Each part would provide requirements that may be used to ensure a consistent approach when specifying the use of coded character sets in functional standards. Since activity on OSI has now come to a halt internationally, it is unlikely that that the remaining parts will be produced.

Within the set of character set standards there are two generic code structures, that defined by ISO/IEC 2022 for 7-bit and 8-bit transport mechanisms and that defined by the new ISO/IEC 10646 for a multiple-octet transport mechanism. It was the intention to cover both of these generic code structures as future parts were prepared. Part 1 is concerned with the ISO/IEC 2022 code structure. The requirements that it specifies apply specifically to Western Europe but they may be applicable also to other regions of the world.

Tutorial guidance

Part 1 of ISO/IEC ISP 12070 is applicable to use of ISO/IEC 2022 code structure in the following cases:

Abstract Syntax Notation One (ASN.1) forms part of the Presentation Layer of the OSI model. It is specified in the four-part standard ISO/IEC 8824, the current edition of which was published in 1995, replacing the second edition of 1990 that was a one-part standard. The ASN.1 standard defines a number of character string types, of which those listed above are a selection.

The last case in the list is particularly relevant for character based data streams and for this reason ISO/IEC ISP 12070-1 is included in this guide. It contains a number of specific conformance requirements which go a long way towards supporting implementation interoperability. These could be used as a checklist for developers but also as requirements to be referenced during the procurement process.

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