Overview
ISO 5426:1983 - "Extension of the Latin alphabet coded character set for bibliographic information interchange" defines an extended, coded Latin-character repertoire intended for bibliographic data exchange. The standard specifies a set of 76 graphic characters with coded representations, presented as a code table and a legend that shows each graphic, its intended use and its name. ISO 5426 is aimed primarily at interchange between data-processing systems and within message transmission systems for international bibliographic information.
Key topics and technical requirements
- Character set content: Includes 76 graphic characters covering three types:
- Symbols (punctuation, currency signs, typographic marks)
- Diacritic signs (accent marks, cedillas, macrons, underdots, double accents)
- Particular alphabetic letters (national letters and digraphs used in cataloguing and transliteration)
- Code table and legend: Each character is defined by position, graphic example, use-case and name.
- Composition rules:
- Diacritics are encoded to precede the base character and composed in reading order.
- Characters formed by overprinting a diacritic on a base glyph may be coded as a single character; where the qualifier is separate, components are encoded separately.
- Non-assigned code positions in the table must not be used for international bibliographic interchange.
- ISO 2022 / ISO 2375 compatibility: The standard is designed to operate with ISO 2022 techniques for code extension and uses ISO 2375 procedures for escape-sequence selection of the set (G0–G3 areas). It also aligns with the international reference version of ISO 646 for basic Latin positions, with restrictions on certain ISO 646 positions when combined.
- Notes and implementation guidance: The document includes explanatory notes and cross-references to materialization and transmission standards (e.g., error control, magnetic tape, punched-card representations).
Applications and who uses it
- Library systems and bibliographic databases: Ensures consistent encoding of author names, titles and annotations that require extended Latin letters and diacritics.
- Metadata exchange and interoperability: Used in message transmission between cataloguing systems, bibliographic networks and data-processing systems handling international collections.
- Vendors and implementers of character-encoding systems: Developers of cataloguing software, data converters, and interoperability tools that must support legacy or standardized bibliographic encodings.
- Cataloguing standards bodies and archivists: For preservation of accurate character representation across systems and during transliteration.
Related standards
Keywords: ISO 5426, ISO 5426:1983, extension of the Latin alphabet, coded character set, bibliographic information interchange, diacritics, character encoding, ISO 2022, ISO 646.
