Жапон тілінің алғашқы электрондық таңбалау кодировкасы (JIS X 0201)

Japanese single byte character encoding

JIS X 0201, a Japanese Industrial Standard developed in 1969, was the first Japanese electronic character set to become widely used. The character set was initially known as JIS C 6220 before the JIS category reform. Its two forms were a 7 bit encoding or an 8 bit encoding, although the 8 bit form was dominant until Unicode (specifically UTF 8) replaced it. The full name of this standard is 7 bit and 8 bit coded character sets for information interchange (7ビット及び8ビットの情報交換用符号化文字集合). The first 96 codes comprise an ISO 646 variant, mostly following ASCII with some differences, while the second 96 character codes represent the phonetic Japanese katakana signs. Since the encoding does not provide any way to express hiragana or kanji, it is only capable of expressing simplified written Japanese. Nevertheless, this simplification can represent the full range of sounds in the language. In the 1970s, this was acceptable for media such as text mode computer terminals, telegrams, receipts, or other electronically handled data. JIS X 0201 was supplanted by subsequent encodings such as Shift JIS, which combines this standard and JIS X 0208, and later by Unicode.

The Comite Consultatif International Telephonique et Telegraphique (CCITT) introduced the International Telegraph Alphabet No.2 (ITA2) code as an international standard, which was the 5 bit Latin encoding. Most countries have their own national standards based on this. In Japan, the Agency of Industrial Science and Technology (AIST) standardized it as the 6 bit character codes of JIS C 0803 1961 (Keyboard layout and codes for teleprinters), which combined with katakana characters. However, it didn't match the industry requirements because the character map was small, and the code layout was impractical. The AIST considered a practical character encoding to replace various codes used in Japan. In 1963, ISO introduced a draft of ISO R 646 (6 and 7 bit coded character sets for information processing interchange). AIST committed the conjunction of ISO R 646 and katakana mapping to the Information Processing Society of Japan (IPSJ). IPSJ formed the code standardization committee. The committee didn't adopt the 6 bit form of ISO's draft because the katakana set couldn't fit into its character map. The early JIS draft mapped small katakana characters next to each of their normal katakana characters. It was considered to be convenient for sorting by Gojūon order (JIS X 0208:1978 chose this ordering). Some committee members criticized it would complicate the mechanic of keyboards which only handled normal katakana characters. The later draft mapped small katakana characters to positions 0xA7 0xAF. The 1964 ISO draft reserved the positions 0x24 and 0x5c for first and second currency symbols to be assigned by each country, but it was considered too dangerous in international communications to use currency symbols that could be localized. The ISO committee had two options that to use a generic currency symbol (¤) or to give the dollar ($) and pound (£) signs permanent assignments. It was agreed that the dollar sign was assigned to position 0x24 and the pound sign was to position 0x23. The latter was not required in countries that did not need the pound sign. The JIS committee decided to put the yen sign (¥) in 0x5c (one of national use positions). JIS C 6220 (Codes for information interchange, 情報交換用符号) was published in 1969. Its number was changed to JIS X 0201 due to the JIS category reform in 1987, and the name was changed to 7 bit and 8 bit coded character sets for information interchange (7ビット及び8ビットの情報交換用符号化文字集合) in the 1990 edition. The character set of JIS X 0201 had been widely used in Japan. The Nationwide Banking Data Communication System (全国銀行データ通信システム), the largest funds transfer system in Japan, was established in 1973. Transaction messages between banks used a subset of JIS X 0201. The system was used until 2018, and it was replaced by the ZEDI (The Nationwide Banking Electronic Data Interchange System, 全銀EDIシステム) which could handle hiragana and kanji characters. In 1978, the JIS C 6226 (JIS X 0208) 2 byte character set was developed to express hiragana and kanji characters. It includes katakana characters, but their codes and layout are different from JIS X 0201. Computer manufacturers developed their own extensions of JIS X 0208 to retain compatibility with JIS X 0201. In 1982, the Microsoft Kanji encoding scheme (Codepage 932 of MS DOS) and Digital Research's SJC26 (for Japanese CP/M 86) were developed to combine JIS X 0201 single byte encoding and JIS X 0208 double byte encoding without shift out and shift in characters. They were called Shift JIS, which became the industrial standard for personal computers.

The first half (Roman set) of JIS X 0201 constitutes a Japanese variant of ISO 646, amounting to ASCII with backslash (\) and tilde (~) replaced by yen (¥) and overline (‾), while the second half (Kana set) consists mainly of katakana. Control characters are specified in JIS X 0211. In the 7 bit format, the shift out control character (0x0E) switches to the Kana set and shift in (0x0F) switches to the Roman set. In the 8 bit format, given in the chart below, bytes with the most significant bit set (i. e. 0x80–0xFF) are used for the Kana set and bytes with it unset (i. e. 0x00–0x7F) are used otherwise. Names used specifically for the 7 bit Roman set include "JISCII", "JIS Roman", "ISO646 JP", "JIS C6220 1969 ro", "Japan 7 Bit Latin", and "ISO IR 14", Another similar problem is C programming language's control characters of string literals, like printf("Hello, world.¥n");.