KOI-7

KOI-7 (КОИ-7) is a 7-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet.

Short KOI

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

KOI-7 Switched

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
0_ 0	NUL 0000	SOH 0001	STX 0002	ETX 0003	EOT 0004	ENQ 0005	ACK 0006	BEL 0007	BS 0008	HT 0009	LF 000A	VT 000B	FF 000C	CR 000D	SO 000E	SI 000F
1_ 16	DLE 0010	DC1 0011	DC2 0012	DC3 0013	DC4 0014	NAK 0015	SYN 0016	ETB 0017	CAN 0018	EM 0019	SUB 001A	ESC 001B	FS 001C	GS 001D	RS 001E	US 001F
2_ 32	SP 0020	! 0021	" 0022	# 0023	¤/$ 00A4/0024	% 0025	& 0026	' 0027	( 0028	) 0029	* 002A	+ 002B	, 002C	- 002D	. 002E	/ 002F
3_ 48	0 0030	1 0031	2 0032	3 0033	4 0034	5 0035	6 0036	7 0037	8 0038	9 0039	: 003A	; 003B	< 003C	= 003D	> 003E	? 003F
4_ 64	@ 0040	A 0041	B 0042	C 0043	D 0044	E 0045	F 0046	G 0047	H 0048	I 0049	J 004A	K 004B	L 004C	M 004D	N 004E	O 004F
5_ 80	P 0050	Q 0051	R 0052	S 0053	T 0054	U 0055	V 0056	W 0057	X 0058	Y 0059	Z 005A	[ 005B	\ 005C	] 005D	^ 005E	_ 005F
6_ 96	` 0060	a 0061	b 0062	c 0063	d 0064	e 0065	f 0066	g 0067	h 0068	i 0069	j 006A	k 006B	l 006C	m 006D	n 006E	o 006F
7_ 112	p 0070	q 0071	r 0072	s 0073	t 0074	u 0075	v 0076	w 0077	x 0078	y 0079	z 007A	{ 007B	| 007C	} 007D	~ 007E	DEL 007F

  Letter   Number   Punctuation   Symbol   Other   Undefined

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
0_ 0	NUL 0000	SOH 0001	STX 0002	ETX 0003	EOT 0004	ENQ 0005	ACK 0006	BEL 0007	BS 0008	HT 0009	LF 000A	VT 000B	FF 000C	CR 000D	SO 000E	SI 000F
1_ 16	DLE 0010	DC1 0011	DC2 0012	DC3 0013	DC4 0014	NAK 0015	SYN 0016	ETB 0017	CAN 0018	EM 0019	SUB 001A	ESC 001B	FS 001C	GS 001D	RS 001E	US 001F
2_ 32	SP 0020	! 0021	" 0022	# 0023	¤/$ 00A4/0024	% 0025	& 0026	' 0027	( 0028	) 0029	* 002A	+ 002B	, 002C	- 002D	. 002E	/ 002F
3_ 48	0 0030	1 0031	2 0032	3 0033	4 0034	5 0035	6 0036	7 0037	8 0038	9 0039	: 003A	; 003B	< 003C	= 003D	> 003E	? 003F
4_ 64	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
5_ 80	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
6_ 96	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
7_ 112	П 041F	Я 042F	Р 0420	С 0421	Т 0422	У 0423	Ж 0416	В 0412	Ь 042C	Ы/Ъ 042B/042A	З 0417	Ш 0428	Э 042D	Щ 0429	Ч 0427	DEL 007F

  Letter   Number   Punctuation   Symbol   Other   Undefined

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
0_ 0	NUL 0000	SOH 0001	STX 0002	ETX 0003	EOT 0004	ENQ 0005	ACK 0006	BEL 0007	BS 0008	HT 0009	LF 000A	VT 000B	FF 000C	CR 000D	SO 000E	SI 000F
1_ 16	DLE 0010	DC1 0011	DC2 0012	DC3 0013	DC4 0014	NAK 0015	SYN 0016	ETB 0017	CAN 0018	EM 0019	SUB 001A	ESC 001B	FS 001C	GS 001D	RS 001E	US 001F
2_ 32	SP 0020	! 0021	" 0022	# 0023	¤/$ 00A4/0024	% 0025	& 0026	' 0027	( 0028	) 0029	* 002A	+ 002B	, 002C	- 002D	. 002E	/ 002F
3_ 48	0 0030	1 0031	2 0032	3 0033	4 0034	5 0035	6 0036	7 0037	8 0038	9 0039	: 003A	; 003B	< 003C	= 003D	> 003E	? 003F
4_ 64	@ 0040	A 0041	B 0042	C 0043	D 0044	E 0045	F 0046	G 0047	H 0048	I 0049	J 004A	K 004B	L 004C	M 004D	N 004E	O 004F
5_ 80	P 0050	Q 0051	R 0052	S 0053	T 0054	U 0055	V 0056	W 0057	X 0058	Y 0059	Z 005A	[ 005B	\ 005C	] 005D	↑/^ 2191/005E	_ 005F
6_ 96	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
7_ 112	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 007F

  Letter   Number   Punctuation   Symbol   Other   Undefined

See also

• KOI character encodings
  • KOI-8
  • KOI8-R
  • KOI8-U
• YUSCII (SLOSCII, CROSCII, SRPSCII, MAKSCII)
• CP 866
• Windows-1251

References

1. 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.
2. 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.
3. Freed, Ned; Dürst, Martin, eds. (2013-12-20). "Character Sets". RFC2978. Archived from the original on 2016-12-03. Retrieved 2016-12-03.
4. Nechayev, Valentin (2013) [2001]. "Review of 8-bit Cyrillic encodings universe". Archived from the original on 2016-12-05. Retrieved 2016-12-05.
5. Clews, John (1988). Language Automation Worldwide - The Development of Character Set Standards (1 ed.). Sesame Computer Projects. ISBN 1-87009501-4.
6. Czyborra, Roman (1998-11-30) [1998-05-25]. "The Cyrillic Charset Soup". Archived from the original on 2016-12-03. Retrieved 2016-12-03.
7. 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.
8. 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.
9. "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" Check |archive-url= value (help). 1.3. Archived from the original on 2017-02-18. Retrieved 2020-06-24.