The standard, directly related to, supersedes all of the ISO 646 and ISO 8859 sets with one unified set of character encodings using a larger 21-bit value.
The series of standards governing 8-bit character encodings supersede the ISO 646 international standard and its national variants, by providing 96 additional characters with the additional bit and thus avoiding any substitution of ASCII codes. Among these exercises, ISO 646:1991 IRV (International Reference Version) is explicitly defined and identical to. This standard allows users to exercise the 12 variable characters (i.e., two alternative graphic characters and 10 national defined characters).
The final 1991 version of the code ISO 646:1991 is also known as, International Reference Alphabet or IRA, formerly (IA5). The original version (ISO 646 IRV) differed from only in that in code point 0x24, ASCII's ($) was replaced by the (¤). As ASCII did not provide a number of characters needed for languages other than English, a number of national variants were made that substituted some less-used characters with needed ones.ĭue to the incompatibility of the various national variants, an International Reference Version (IRV) of ISO/IEC 646 was introduced, in an attempt to at least restrict the replaced set to the same characters in all variants.