KOI-7
KOI-7 (КОИ-7) is a 7-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet.
| Kermit | SHORT-KOI | 
|---|---|
| Alias(es) | KOI-7 N2, ВКД | 
| Language(s) | Russian | 
| Standard | GOST 13052, GOST 27463 | 
| Classification | 7-bit KOI encoding | 
| Preceded by | MTK-2 | 
| Succeeded by | KOI-8 | 
| Other related encoding(s) | YUSCII, ISO 646 | 
| MIME / IANA | KOI7-switched | 
|---|---|
| Alias(es) | csKOI7switched | 
| Language(s) | Russian | 
| Standard | GOST 13052, GOST 27463 | 
| Classification | 7-bit stateful KOI encoding | 
| Transforms / Encodes | ISO 646:IRV (shift-in) KOI-7 N1 (shift-out)  | 
| Preceded by | MTK-2 | 
| Succeeded by | KOI-8 | 
| Other related encoding(s) | YUSCII | 
In Russian, KOI-7 stands for Kod Obmena Informatsiey, 7 bit (Код Обмена Информацией, 7 бит) which means "Code for Information Exchange, 7 bit".[1]
It was first standardized in GOST 13052-67 (with the 2nd revision GOST 13052-74 / ST SEV 356-76) and GOST 27463-87 / ST SEV 356-86.
Shift Out (SO) and Shift In (SI) control characters are used in KOI-7, where SO starts printing Russian letters (KOI-7 N1), and SI starts printing Latin letters again (KOI-7 N0), or for lowercase and uppercase switching. This version is also known as KOI7-switched aka csKOI7switched.[2][3]
On ISO 2022 compatible computer terminals KOI7-switched can be activated by the escape sequence ESC ( @ ESC ) N LS0.[2]
KOI-7 was used on machines like the SM EVM (СМ ЭВМ) and DVK (ДВК); KOI-7 N2 was utilized in the machine-language of the Электроника Д3-28 (Elektronika D3-28) as four-digit hexadecimal code, БЭСМ-6 (BESM-6), where it was called ВКД, (internal data code). The encodings were also used on RSX-11, RT-11 and similar systems.[4]
KOI-7 N0
    
KOI-7 N0[2] (КОИ-7 Н0[1]) is identical to the IRV set in ISO 646:1967.[2] Compared to US-ASCII, the dollar sign ("$") at code point 24 (hex) was replaced by the universal currency sign "¤", but this was not maintained in all cases, in particular not after the fall of the Iron Curtain. Likewise, the IRV set in ISO/IEC 646:1991 also changed the character back to a dollar sign.
| KOI-7 N0 | ||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
| 0x | NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL | BS | HT | LF | VT | FF | CR | SO | SI | 
| 1x | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB | CAN | EM | SUB | ESC | FS | GS | RS | US | 
| 2x | SP | ! | " | # | ¤/$ | % | & | ' | ( | ) | * | + | , | - | . | / | 
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? | 
| 4x | @ | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | 
| 5x | P | Q | R | S | T | U | V | W | X | Y | Z | [ | \ | ] | ^ | _ | 
| 6x | ` | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | 
| 7x | p | q | r | s | t | u | v | w | x | y | z | { | | | } | ~ | DEL | 
KOI-7 N1
    
KOI-7 N1 (КОИ-7 Н1[1]) was first standardized in GOST 13052-67,[5][6][7] and later also in ISO 5427.[2] It is sometimes referred to as "koi-0" as well.[6]
Compared to ASCII and ISO 646 uppercase and lowercase letters are swapped in order to make it easier to recognize Russian text when presented using ASCII.[6]
To trim the alphabet into chunks of 32 characters the dotted Ё/ë was dropped.[6] In order to avoid conflicts with ASCII's and ISO 646's definition as DEL and its usage as EOF marker (-1) in some systems, it dropped the "CAPITAL HARD SIGN" Ъ that would have naturally resided at this location.[6]
In a Bulgarian variant the unnecessary Russian "CAPITAL YERY" Ы at code point 121 was replaced by the "CAPITAL HARD SIGN" Ъ.[6]
| KOI-7 N1[7] | ||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
| 0x | NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL | BS | HT | LF | VT | FF | CR | SO | SI | 
| 1x | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB | CAN | EM | SUB | ESC | FS | GS | RS | US | 
| 2x | SP | ! | " | # | ¤/$ | % | & | ' | ( | ) | * | + | , | - | . | / | 
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? | 
| 4x | ю 044E  | 
а 0430  | 
б 0431  | 
ц 0446  | 
д 0434  | 
е 0435  | 
ф 0444  | 
г 0433  | 
х 0445  | 
и 0438  | 
й 0439  | 
к 043A  | 
л 043B  | 
м 043C  | 
н 043D  | 
о 043E  | 
| 5x | п 043F  | 
я 044F  | 
р 0440  | 
с 0441  | 
т 0442  | 
у 0443  | 
ж 0436  | 
в 0432  | 
ь 044C  | 
ы 044B  | 
з 0437  | 
ш 0448  | 
э 044D  | 
щ 0449  | 
ч 0447  | 
ъ 044A  | 
| 6x | Ю 042E  | 
А 0410  | 
Б 0411  | 
Ц 0426  | 
Д 0414  | 
Е 0415  | 
Ф 0424  | 
Г 0413  | 
Х 0425  | 
И 0418  | 
Й 0419  | 
К 041A  | 
Л 041B  | 
М 041C  | 
Н 041D  | 
О 041E  | 
| 7x | П 041F  | 
Я 042F  | 
Р 0420  | 
С 0421  | 
Т 0422  | 
У 0423  | 
Ж 0416  | 
В 0412  | 
Ь 042C  | 
Ы/Ъ | З 0417  | 
Ш 0428  | 
Э 042D  | 
Щ 0429  | 
Ч 0427  | 
DEL | 
KOI-7 N2
    
KOI-7 N2 (КОИ-7 Н2[1]), like KOI-7 N1, was also standardized in GOST 13052-67.[7]
Kermit names it SHORT-KOI / short-koi.[8][9]
| KOI-7 N2[7][9] | ||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
| 0x | NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL | BS | HT | LF | VT | FF | CR | SO | SI | 
| 1x | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB | CAN | EM | SUB | ESC | FS | GS | RS | US | 
| 2x | SP | ! | " | # | ¤/$ | % | & | ' | ( | ) | * | + | , | - | . | / | 
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? | 
| 4x | @ | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | 
| 5x | P | Q | R | S | T | U | V | W | X | Y | Z | [ | \ | ] | ↑/^ | _ | 
| 6x | Ю 042E  | 
А 0410  | 
Б 0411  | 
Ц 0426  | 
Д 0414  | 
Е 0415  | 
Ф 0424  | 
Г 0413  | 
Х 0425  | 
И 0418  | 
Й 0419  | 
К 041A  | 
Л 041B  | 
М 041C  | 
Н 041D  | 
О 041E  | 
| 7x | П 041F  | 
Я 042F  | 
Р 0420  | 
С 0421  | 
Т 0422  | 
У 0423  | 
Ж 0416  | 
В 0412  | 
Ь 042C  | 
Ы 042B  | 
З 0417  | 
Ш 0428  | 
Э 042D  | 
Щ 0429  | 
Ч 0427  | 
DEL | 
See also
    
    
References
    
- ГОСТ 27463-87. Системы обработки информации. 7-битные кодированные наборы символов (с Изменением N 1) [GOST 27463-87. Information processing systems. 7-bit coded character sets] (in Russian). Госстандарт СССР. 1987-10-29. Archived from the original on 2016-12-03. Retrieved 2016-12-02.
 - Sokolov, Michael (2004-01-23). "Charset name: KOI7-switched". International Free Computing Task Force (IFCTF). Archived from the original on 2016-12-03. Retrieved 2016-12-02.
 - Freed, Ned; Dürst, Martin, eds. (2013-12-20). "Character Sets". RFC2978. Archived from the original on 2016-12-03. Retrieved 2016-12-03.
 - Nechayev, Valentin (2013) [2001]. "Review of 8-bit Cyrillic encodings universe". Archived from the original on 2016-12-05. Retrieved 2016-12-05.
 - Clews, John (1988). Language Automation Worldwide - The Development of Character Set Standards (1 ed.). Sesame Computer Projects. ISBN 1-87009501-4.
 - Czyborra, Roman (1998-11-30) [1998-05-25]. "The Cyrillic Charset Soup". Archived from the original on 2016-12-03. Retrieved 2016-12-03.
 - Hohlov, Yu. E. "Cyrillic Information Representation in Electronic Form - Character Set (Code Page) Tables". Archived from the original on 2016-12-05. Retrieved 2016-12-05.
 - da Cruz, Frank (2010-04-02). "Kermit and MIME Character-Set Names". The Kermit Project. Columbia University, New York, USA. Archived from the original on 2016-12-03. Retrieved 2016-12-02.
 - "SHORT KOI (KOI-7)". Kermit. Columbia University. Retrieved 2020-06-24.
 
Further reading
    
- Kornai, Andras; Birnbaum, David J.; da Cruz, Frank; Davis, Bur; Fowler, George; Paine, Richard B.; Paperno, Slava; Simonsen, Keld J.; Thobe, Glenn E.; Vulis, Dimitri; van Wingen, Johan W. (1993-03-13). --> "CYRILLIC ENCODING FAQ Version 1.3". 1.3. Archived from the original on 2017-02-18. Retrieved 2020-06-24. 
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