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Unicode and ISO 10646

Q: What is the relation between ISO/IEC 10646 and Unicode?

A: In 1991, the ISO Working Group responsible for ISO/IEC 10646 (JTC 1/SC 2/WG 2) and the Unicode Consortium decided to create one universal standard for coding multilingual text. Since then, the ISO 10646 Working Group (SC 2/WG 2) and the Unicode Consortium have worked together very closely to extend the standard and to keep their respective versions synchronized. [EH] & [KW]

Q: So are they the same thing?

A: No. Although the character codes and encoding forms are synchronized between Unicode and ISO/IEC 10646, the Unicode Standard imposes additional constraints on implementations to ensure that they treat characters uniformly across platforms and applications. To this end, it supplies an extensive set of functional character specifications, character data, algorithms and substantial background material that is not in ISO/IEC 10646. [KW]

Q: Where do I find out which version of ISO/IEC 10646 is equivalent to a given version of the Unicode Standard?

A: Each version of the Unicode Standard identifies the corresponding version of ISO/IEC 10646. Start with http://www.unicode.org/versions/ and look at the the link to the main document for each version (under "Related links"). Some versions of the Unicode standard are synchronized to a combination of ISO/IEC 10646 and one or more amendments.  [AF]

Q: How do I get a copy of ISO/IEC 10646 ?

A: You can order copies of ISO/IEC 10646 and its amendments directly from the ISO Store or from the ANSI e-Standards Store. The entire publication is on CD-ROM, which accounts for its relatively low price, given the size of the standard. [KW]

Q: Is ISO/IEC 10646 also available for free download?

A: Yes. ISO/IEC 10646:2003 (E), ISOIEC 10646:2003 (F), Amendment 1:2005 (E), Amendment 1:2005 (F), Amendment 2:2006 (E), Amendment 2:2006 (F), Amendment 3:2008 (E), Amendment 4:2008 (E), and Amendment 5:2008 (E) are all available for free download from: http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html. The "(E)" and "(F)" refer to the English and French versions of the standard, respectively. [KW]

Q: How do I get a copy of ISO/IEC 10646 that is equivalent to Unicode 5.0?

A: Unicode 5.0 has the same character repertoire as ISO/IEC 10646:2003 with Amendments 1 and 2 applied. ISO/IEC 10646:2003 can either be purchased on CD-ROM or can be downloaded for free. By itself, ISO/IEC 10646:2003 is equivalent to the repertoire of Unicode 4.0, so to obtain a version equivalent to Unicode 5.0, you must also order (or download) the two amendments, which add more characters to the standard. [KW]

Q: How do I get a copy of ISO/IEC 10646 that is equivalent to Unicode 5.2?

A: Unicode 5.2 adds the repertoire from Amendments 3 through 6, as well. Amendments 3 through 5 are available now for order or download. Amendment 6 is still in its final publication process, but should be available from ISO soon. [KW]