KOI8-U

KOI8-U is an 8-bit character encoding, designed to cover Ukrainian, which uses a Cyrillic alphabet. It is based on KOI8-R, which covers Russian and Bulgarian, but replaces eight graphic characters with four Ukrainian letters Ґ, Є, І, and Ї in both upper case and lower case.

In Microsoft Windows, KOI8-U is assigned the code page number 21866. In IBM, KOI8-U is assigned code page 1168.^[1]

KOI8 remains much more commonly used than ISO 8859-5, which never really caught on. Another common Cyrillic character encoding is Windows-1251. In the future, both may eventually give way to Unicode.

KOI8 stands for Kod Obmena Informatsiey, 8 bit (Russian: Код Обмена Информацией, 8 бит) which means "Code for Information Exchange, 8 bit".

The KOI8 character sets have the property that the Russian Cyrillic letters are in pseudo-Roman order rather than the natural Cyrillic alphabetical order as in ISO 8859-5. Although this may seem unnatural, it has the useful property that if the 8th bit is stripped, the text can still be read (or at least deciphered) in case-reversed transliteration on an ordinary ASCII terminal. For instance, "Русский Текст" in KOI8-U becomes rUSSKIJ tEKST ("Russian Text") if the 8th bit is stripped.

Codepage layout

The following table shows the KOI8-U encoding.^[1] Each character is shown with its equivalent Unicode code point and its decimal code point.

KOI8-U

	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F
0_
1_
2_	SP 0020 32	! 0021 33	" 0022 34	# 0023 35	$ 0024 36	% 0025 37	& 0026 38	' 0027 39	( 0028 40	) 0029 41	* 002A 42	+ 002B 43	, 002C 44	- 002D 45	. 002E 46	/ 002F 47
3_	0 0030 48	1 0031 49	2 0032 50	3 0033 51	4 0034 52	5 0035 53	6 0036 54	7 0037 55	8 0038 56	9 0039 57	: 003A 58	; 003B 59	< 003C 60	= 003D 61	> 003E 62	? 003F 63
4_	@ 0040 64	A 0041 65	B 0042 66	C 0043 67	D 0044 68	E 0045 69	F 0046 70	G 0047 71	H 0048 72	I 0049 73	J 004A 74	K 004B 75	L 004C 76	M 004D 77	N 004E 78	O 004F 79
5_	P 0050 80	Q 0051 81	R 0052 82	S 0053 83	T 0054 84	U 0055 85	V 0056 86	W 0057 87	X 0058 88	Y 0059 89	Z 005A 90	[ 005B 91	\ 005C 92	] 005D 93	^ 005E 94	_ 005F 95
6_	` 0060 96	a 0061 97	b 0062 98	c 0063 99	d 0064 100	e 0065 101	f 0066 102	g 0067 103	h 0068 104	i 0069 105	j 006A 106	k 006B 107	l 006C 108	m 006D 109	n 006E 110	o 006F 111
7_	p 0070 112	q 0071 113	r 0072 114	s 0073 115	t 0074 116	u 0075 117	v 0076 118	w 0077 119	x 0078 120	y 0079 121	z 007A 122	{ 007B 123	| 007C 124	} 007D 125	~ 007E 126
8_	─ 2500 128	│ 2502 129	┌ 250C 130	┐ 2510 131	└ 2514 132	┘ 2518 133	├ 251C 134	┤ 2524 135	┬ 252C 136	┴ 2534 137	┼ 253C 138	▀ 2580 139	▄ 2584 140	█ 2588 141	▌ 258C 142	▐ 2590 143
9_	░ 2591 144	▒ 2592 145	▓ 2593 146	⌠ 2320 147	■ 25A0 148	∙ 2219 149	√ 221A 150	≈ 2248 151	≤ 2264 152	≥ 2265 153	NBSP 00A0 154	⌡ 2321 155	° 00B0 156	² 00B2 157	· 00B7 158	÷ 00F7 159
A_	═ 2550 160	║ 2551 161	╒ 2552 162	ё 0451 163	є 0454 164	╔ 2554 165	і 0456 166	ї 0457 167	╗ 2557 168	╘ 2558 169	╙ 2559 170	╚ 255A 171	╛ 255B 172	ґ 0491 173	╝ 255D 174	╞ 255E 175
B_	╟ 255F 176	╠ 2560 177	╡ 2561 178	Ё 0401 179	Є 0404 180	╣ 2563 181	І 0406 182	Ї 0407 183	╦ 2566 184	╧ 2567 185	╨ 2568 186	╩ 2569 187	╪ 256A 188	Ґ 0490 189	╬ 256C 190	© 00A9 191
C_	ю 044E 192	а 0430 193	б 0431 194	ц 0446 195	д 0434 196	е 0435 197	ф 0444 198	г 0433 199	х 0445 200	и 0438 201	й 0439 202	к 043A 203	л 043B 204	м 043C 205	н 043D 206	о 043E 207
D_	п 043F 208	я 044F 209	р 0440 210	с 0441 211	т 0442 212	у 0443 213	ж 0436 214	в 0432 215	ь 044C 216	ы 044B 217	з 0437 218	ш 0448 219	э 044D 220	щ 0449 221	ч 0447 222	ъ 044A 223
E_	Ю 042E 224	А 0410 225	Б 0411 226	Ц 0426 227	Д 0414 228	Е 0415 229	Ф 0424 230	Г 0413 231	Х 0425 232	И 0418 233	Й 0419 234	К 041A 235	Л 041B 236	М 041C 237	Н 041D 238	О 041E 239
F_	П 041F 240	Я 042F 241	Р 0420 242	С 0421 243	Т 0422 244	У 0423 245	Ж 0416 246	В 0412 247	Ь 042C 248	Ы 042B 249	З 0417 250	Ш 0428 251	Э 042D 252	Щ 0429 253	Ч 0427 254	Ъ 042A 255
	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F

In the table above, 20 is the regular SPACE character, and 9A is the NO-BREAK SPACE.

The difference with KOI8-R consists of the positions 0xA4; 0xA6; 0xA7; 0xAD; and 0xB4; 0xB6; 0xB7; 0xBD; which consist of extra letters that don't exist in Russian.

Although RFC 2319 says that character 95 should be U+2219 (∙), it may also be U+2022 (•) to match the bullet character in Windows-1251.

Some references have a typo and incorrectly state that character B4 is U+0403, rather than the correct U+0404. This typo is present in Appendix A of RFC 2319 (but the table in the main text of the RFC gives the correct mapping).

See also

• Ukrainian alphabet

References

1. "CPGID 01168". Code page identifiers. IBM. Retrieved 2012-10-25.

External links

• RFC 2319
• IBM CDRA