ISO/IEC 646

ASCII1963-infobox-paths

ASCII-infobox

ISO-646-JP-paths

ISO/IEC 646 is an international standard for character encoding that was developed by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It is a 7-bit character set, which means it can represent up to 128 different characters. This standard is also known as the International Reference Alphabet (IRA), formerly International Alphabet No. 5 (IA5). It is essentially equivalent to the American Standard Code for Information Interchange (ASCII), with a few exceptions for national variations.

Overview

ISO/IEC 646 was first published in 1967. The main purpose of ISO/IEC 646 was to facilitate international communication in the computing, telecommunications, and information technology sectors by providing a common set of characters. It includes letters, digits, punctuation marks, and control characters. While it forms the basis for ASCII, ISO/IEC 646 also allows for national variations to accommodate characters specific to languages other than English. These variations replace certain characters in the ASCII set with characters needed for other languages.

National Variations

Several countries or regions have developed their own variations of ISO/IEC 646 to include characters specific to their languages. These variations often replace characters such as the dollar sign ($), hash (#), and the square brackets ([ ]) with letters such as Æ, Ø, and Å for Nordic countries, or ß and ü for German-speaking countries. Examples of national variations include:

• ISO 646-GB (United Kingdom)
• ISO 646-FR (France)
• ISO 646-DE (Germany)
• ISO 646-CA (Canada, for French language)
• ISO 646-SE (Sweden)

Each national version of ISO/IEC 646 is designated by a two-letter country code following the standard's number.

Impact and Legacy

The development of ISO/IEC 646 was a significant step towards standardization in the early days of computer technology. It laid the groundwork for later, more comprehensive character encoding standards, such as ISO/IEC 8859 and Unicode, which support a much wider array of characters from languages around the world. Despite its limitations, ISO/IEC 646 played a crucial role in the history of computing and information technology.

See Also

• Character encoding
• ASCII
• ISO/IEC 8859
• Unicode