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VSCII

VSCII
Alias(es)x-viet-tcvn5712[1]
Language(s)Vietnamese, English
Created byTCVN/TC1
StandardTCVN 5712:1993
Classification8-bit SBCS;
Extended ASCII (VSCII-2/-3)

VSCII (Vietnamese Standard Code for Information Interchange), also known as TCVN 5712,[2] ISO-IR-180,[3] .VN,[4] ABC[4] or simply the TCVN encodings,[4][5] is a set of three closely related Vietnamese national standard character encodings for using the Vietnamese language with computers, developed by the TCVN Technical Committee on Information Technology (TCVN/TC1) and first adopted in 1993 (as TCVN 5712:1993).[2]

VSCII (TCVN) was used extensively in the north of Vietnam, while VNI was popular in the south.[4] It should not be confused with the similarly-named unofficial VISCII encoding, which was sometimes used by overseas Vietnamese speakers.[4] Unicode and the Windows-1258 code page are now used for virtually all Vietnamese computer data, but legacy files or archived messages may need conversion.

Encodings

All three forms of VSCII keep the 95 printable characters of ASCII unmodified.

VSCII-3, also known as TCVN 5712-3, VN3 or simply TCVN3,[6] includes the fewest assignments. It is an extended ASCII, because it keeps all 128 codes of ASCII unmodified. It does not re-assign any of the C0 and C1 control codes. Compared to ASCII, it adds 75 characters:

  • 67 lowercase characters, allowing full lowercase support.
  • 7 uppercase characters, allowing uppercase support for the 29 base letters without tone marks.
  • The non-breaking space.

Tone marks on uppercase vowels is accomplished in TCVN3 by switching to an all-capital font.[7]

VSCII-2, also known as TCVN 5712-2 and VN2, is a superset of VSCII-3. It is an extended ASCII, because it keeps all 128 codes of ASCII unmodified. It does not re-assign any of the C0 and C1 control codes, making it conformant with ISO 2022 as a 96-set.[2][3] Compared to VSCII-3, it adds (for a total of 96 non-ASCII characters):

  • 16 more uppercase characters with pre-composed tone marks (for a total of 23 non-ASCII uppercase characters)
  • 5 combining diacritics for tone marks, allowing other combinations of uppercase letters and tone marks to be represented. Combining marks follow the base letter[2] as in VNI (rather than preceding them as in ANSEL).

VSCII-1, also known as TCVN 5712-1 and VN1, is an extension of VSCII-2, and is a modified ASCII, since it replaces 12 of the 33 control characters with precomposed characters. Compared to VSCII-2, it (for a total of 140 non-ASCII characters):

  • Adds 44 more pre-composed uppercase letters, bringing them to the same count as the lowercase
  • Does this by replacing 12 ASCII control characters and allocating 32 graphical characters to the C1 control area, breaking ISO 2022 compatibility

Conversion from VSCII-3 to VSCII-2 or VSCII-1 and conversion from VSCII-2 to VSCII-1 are not necessary, but can result in smaller files.

Conversion from VSCII-1 to VSCII-2 or VSCII-3 and conversion from VSCII-2 to VSCII-3 require expansion of some pre-composed characters.

Character set

VSCII-1[2]
_0 _1 _2 _3 _4 _5 _6 _7 _8 _9 _A _B _C _D _E _F
0_
0
NUL
0000
Ú
00DA

1EE4
ETX
0003

1EEA

1EEC

1EEE
BEL
0007
BS
0008
HT
0009
LF
000A
VT
000B
FF
000C
CR
000D
SO
000E
SI
000F
1_
16
DLE
0010

1EE8

1EF0

1EF2

1EF6

1EF8
Ý
00DD

1EF4
CAN
0018
EM
0019
SUB
001A
ESC
001B
FS
001C
GS
001D
RS
001E
US
001F
2_
32
SP
0020
!
0021
"
0022
#
0023
$
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
8_
128
À
00C0

1EA2
Ã
00C3
Á
00C1

1EA0

1EB6

1EAC
È
00C8

1EBA

1EBC
É
00C9

1EB8

1EC6
Ì
00CC

1EC8
Ĩ
0128
9_
144
Í
00CD

1ECA
Ò
00D2

1ECE
Õ
00D5
Ó
00D3

1ECC

1ED8

1EDC

1EDE

1EE0

1EDA

1EE2
Ù
00D9

1EE6
Ũ
0168
A_
160
NBSP
00A0
Ă
0102
Â
00C2
Ê
00CA
Ô
00D4
Ơ
01A0
Ư
01AF
Đ
0110
ă
0103
â
00E2
ê
00EA
ô
00F4
ơ
01A1
ư
01B0
đ
0111

1EB0
B_
176
̀
0300
̉
0309
̃
0303
́
0301
̣
0323
à
00E0

1EA3
ã
00E3
á
00E1

1EA1

1EB2

1EB1

1EB3

1EB5

1EAF

1EB4
C_
192

1EAE

1EA6

1EA8

1EAA

1EA4

1EC0

1EB7

1EA7

1EA9

1EAB

1EA5

1EAD
è
00E8

1EC2

1EBB

1EBD
D_
208
é
00E9

1EB9

1EC1

1EC3

1EC5
ế
1EBF

1EC7
ì
00EC

1EC9

1EC4

1EBE

1ED2
ĩ
0129
í
00ED

1ECB
ò
00F2
E_
224

1ED4

1ECF
õ
00F5
ó
00F3

1ECD

1ED3

1ED5

1ED7

1ED1

1ED9

1EDD

1EDF

1EE1

1EDB

1EE3
ù
00F9
F_
240

1ED6

1EE7
ũ
0169
ú
00FA

1EE5

1EEB

1EED

1EEF

1EE9

1EF1

1EF3

1EF7

1EF9
ý
00FD

1EF5

1ED0

  Letter   Number   Punctuation   Symbol   Other  Undefined

Checkerboard shading indicates characters that are not in VSCII-3. The shaded characters in rows 0_, 1_, 8_, and 9_ are not in VSCII-2 or VSCII-3.

References

  1. ^ Sivonen, Henri (2014-09-26). "Character encoding changes in m-c require c-c action". mozilla.dev.apps.thunderbird.
  2. ^ a b c d e "[news] TCVN 5712:1993 (VSCII) -- Vietnamese national standard". 1993-06-02. Archived from the original on 2017-01-11.
  3. ^ a b TVCN (1993). "ISO-IR-180: Right-hand Part of the VSCII-2 Code Table" (PDF). ITSCJ/IPSJ.
  4. ^ a b c d e Ngo, Hoc Dinh; Tran, TuBinh. "5. Why Having Vietnamese Charset (Character Set – Encoding) Conversion?". Some special functions of WinVNKey.
  5. ^ Nguyen, Minh T. "Vietnamese Conversions (Vietnet/VIQR, VNI, VPS, VISCII, VNU, TCVN, VietWare, unicode)".
  6. ^ "Unicode & Vietnamese Legacy Character Encodings". Vietnamese Unicode FAQs.
  7. ^ "Unicode & Vietnamese Legacy Character Encodings". Vietnamese Unicode FAQs. TCVN3 is not double-byte, but due to the nature of its encoding, capital letters (vowels) are mapped to a separate, capital font that is similar to the normal, lowercase one.

External links