ISO 8859-6

ISO/IEC 8859-6:1999, Information technology — 8-bit single-byte coded graphic character sets — Part 6: Latin/Arabic alphabet, is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1987. It is informally referred to as Latin/Arabic. It was designed to cover Arabic. Only nominal letters are encoded, no preshaped forms of the letters, so shaping processing is required for display. It does not include the extra letters needed to write most Arabic-script languages other than Arabic itself (such as Persian, Urdu, etc.).

ISO-8859-6 is the IANA preferred charset name for this standard when supplemented with the C0 and C1 control codes from ISO/IEC 6429. The text is in logical order, so bidi processing is required for display. Nominally ISO-8859-6 (code page 28596) is for “visual order”, and ISO-8859-6-I (code page 38596) is for logical order. But in practice, and required for HTML and XML documents, ISO-8859-6 also stands for logical order text. There is also ISO-8859-6-E which supposedly requires directionality to be explicitly specified with special control characters; this latter variant is in practice unused. IBM has assigned code page 1089 to ISO 8859-6. It is an emulation for their AIX operating system.

ASMO 708 was devised by the now defunct Arab Standardization and Metrology Organization in 1986 to be the 8-bit standard to be used in Arabic-speaking countries. The design of this character set was inspired by the previous 7-bit standard — ASMO 449 — but it is not simply the 7-bit character set moved to the upper part; there are some differences.

ASMO 708 is a bidirectional character set. The lower part of the character set differs from standard ISO 646 in the digits and in some punctuation. Depending on the context (whether the numbers are within Latin script or Arabic script), the digits are rendered either as Latin digits or Arabic digits. Also, depending on the context, symmetrical punctuation marks are reversed, i.e., whenever there is an opening punctuation mark, the shape is rendered differently according to the direction of the script.

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