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

References

  1. 1 2 "CPGID 01168". Code page identifiers. IBM. Retrieved 2012-10-25.

External links

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