ISO-IR-165

The CCITT Chinese Primary Set[2] is a multi-byte graphic character set for Chinese communications created for the Consultative Committee on International Telephone and Telegraph (CCITT) in 1992.[3] It is defined in ITU T.101, annex C, which codifies Data Syntax 2 Videotex.[2] It is registered with the ISO-IR registry for use with ISO/IEC 2022 as ISO-IR-165,[4] and encodable in the ISO-2022-CN-EXT code version.[1]

CCITT Chinese set (ISO-IR 165)
MIME / IANAiso-ir-165
Alias(es)CN-GB-ISOIR165 (EUC form)[1]
Language(s)Simplified Chinese, English, Russian
Partial support:
Greek, Japanese
StandardITU T.101, annex C
DefinitionsISO-IR 165
ExtendsGB 2312
Encoding formatsISO-2022-CN-EXT, Videotex Data Syntax 2
Succeeded byGB 18030

It is an extended modification of GB 2312-80, and corresponds to the union of the Mainland Chinese GB standards GB 6345.1-86 and GB 8565.2-88, with some further modification and extensions. A subset of the GB 6345.1 extensions are incorporated into GB 18030, while GB 8565.2 serves as the Mainland Chinese source reference for certain CJK Unified Ideographs.

GB 6345.1

GB 6345.1-86 (32 × 32 Dot Matrix Font Set of Chinese Ideographs for Information Interchange) includes both a corrigendum and an extension for GB 2312. The corrigendum alters the following two characters:[3]

Alterations made to existing GB 2312 characters by GB 6345.1[3]
Row-cellEUCUnamendedGB 6341.1Notes
03-71 0xA3E7ɡ[lower-alpha 1]
79-81 0xEFF1鍾锺[lower-alpha 2]
  1. Corresponds to U+FF47 ｇ in Unicode; however, the unamended reference glyph can also correspond to U+0261 ɡ . See below for how U+0261 is mapped to/from GB 6341.1, versus how it is mapped to/from ISO-IR-165.
  2. The unamended reference glyph is a Traditional Chinese character corresponding to U+937E. The character in question is usually replaced with 钟 (U+949F, also the simplification of 鐘) in Simplified Chinese except in names of persons; the amended glyph is an alternate simplified form corresponding to U+953A.

Deployed implementations incorporating GB 2312, such as Windows code page 936, generally follow these corrections when selecting their Unicode mappings.[5]

The extension adds half-width ISO 646-CN characters in row 10 (in addition to the existing full-width characters in row 3), extends the set of 26 non-ASCII pinyin characters in row 8 with six additional such characters, and adds half-width forms of these 32 pinyin characters to row 11.[3] These GB 6345.1 extensions are also incorporated into GB/T 12345, the Traditional Chinese counterpart to GB 2312, in addition to 29 vertical presentation forms in row 6.[3][6]

The six additional pinyin characters from GB 6345.1 and the vertical presentation forms from GB 12345, but not the half-width forms, are included in the classic Mac OS encoding for Simplified Chinese (a modification of EUC-CN),[7] and also as two-byte codes in GB 18030.[8] The additional pinyin characters are as follows:[7]

Extensions made by GB 6345.1 to GB 2312 row 8
Row-cellEUCCharacter[7][8]Notes
08-27 0xA8BBU+0251 ɑ
08-28 0xA8BCU+1E3F ḿ [lower-alpha 1]
08-29 0xA8BDU+0144 ń
08-30 0xA8BEU+0148 ň
08-31 0xA8BFU+01F9 ǹ [lower-alpha 2]
08-32 0xA8C0U+0261 ɡ [lower-alpha 3]
  1. Mapped to the Private Use Area U+E7C7 by the first (2000) edition of GB 18030; this was amended by the 2005 edition.[8]
  2. This composed character was added in Unicode 3.0. Prior to this, this character was mapped to its composition sequence (i.e. U+006E+0300) by Apple.[7] This change predates the stabilisation of Unicode normalisation forms, which was introduced in Unicode 3.1.[9]
  3. Matches the unamended reference glyph for 03-71 (see above). ISO-IR-165 differs here (see below).

GB 8565.2

GB 8565.2-88 (Information Processing - Coded Character Sets for Text Communication - Part 2: Graphic Characters) defines an extension for GB 2312, adding 705 characters between rows 13–15 and 90–94, of which 69 (all in row 15) are non-hanzi. It includes the GB 2312 corrections from GB 6345.1, but not its extensions.[3]

The Unihan database references GB 8565.2 as the Mainland Chinese source of several hanzi included in Unicode. Its Unihan source abbreviation is G8.[2]

CCITT changes

ISO-IR-165 incorporates the GB 2312 extensions from both GB 6345.1-86 and GB 8565.2-88.[3] Additionally, it adds 161 further characters (including 139 hanzi, identified as “general Chinese characters and variants”).[3][4] These CCITT hanzi extensions have on occasion been mistaken for standard GB 8565.2 characters, including in previous revisions of the Unihan database.[2] In total the set contains 8446 characters.

A number of patterned semigraphic characters are included in row 6.[4] This collides with the vertical presentation forms included in other extensions such as Mac OS Simplified Chinese[7] and GB 18030.[8]

The GB 6345.1 corrections to GB 2312 are only partly applied, resulting in two Unicode mappings being reversed compared to other encodings which include GB 2312 with GB 6345.1 extensions:

Row-cellEUCGB 2312 (unamended)GB 6341.1GB 6341.1 mapping[7][8]ISO-IR-165[4]ISO-IR-165 mapping[10]
03-71 0xA3E7ɡU+FF47ɡU+0261
08-32 0xA8C0(absent)ɡU+0261U+FF47
79-81 0xEFF1鍾锺U+953A锺U+953A

References
  1. Zhu, HF.; Hu, DY.; Wang, ZG.; Kao, TC.; Chang, WCH.; Crispin, M. (1996). "Chinese Character Encoding for Internet Messages". Requests for Comments. IETF. doi:10.17487/rfc1922. RFC 1922.
  2. Chung, Jaemin (2018-01-24). "Pseudo-G8 characters" (PDF). ISO/IEC JTC 1/SC 2/WG 2/IRG N2276.
  3. Lunde, Ken (2009). CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing (2nd ed.). Sebastopol, CA: O'Reilly. pp. 94–111. ISBN 978-0-596-51447-1.
  4. CCITT (1992-07-13). Codes of the Chinese graphic character set for communication (PDF). ITSCJ/IPSJ. ISO-IR-165.
  5. Steele, Shawn (2000). "cp936 to Unicode table". Microsoft, Unicode Consortium.
  6. Lunde, Ken (1998). "Appendix F: GB/T 12345" (PDF). CJKV Information Processing. O'Reilly Media. ISBN 9781565922242.
  7. "Map (external version) from Mac OS Chinese Simplified encoding to Unicode 3.0 and later". Apple, Inc.
  8. Standardization Administration of China (SAC) (2005-11-18). GB 18030-2005: Information Technology—Chinese coded character set.
  9. "Unicode Character Encoding Stability Policies". Unicode Consortium. 2017-06-23.
  10. Viswanadha, Raghuram (2000-08-30). "Unicode to ISO-IR-165 table". International Components for Unicode. IBM. (Note: codes are listed in the source in 7-bit form: add 0x80 to each byte for EUC form, or subtract 0x20 for kuten form)
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