VISCII

From Wikipedia, the free encyclopedia

The Vietnamese Standard Code for Information Interchange (VISCII) is a character set comprising the Vietnamese alphabet, punctuation, and other graphemes. Vietnamese requires slightly too many (134) letter/diacritic combinations to make a traditional extended ASCII character set for it. There are essentially 3 possible solutions to this.

Use a variable width encoding
Use combining diacritical marks, as Windows-1258 does
Replace something from ASCII

VISCII went for the last option, replacing 6 of the least problematic (e.g., least likely to be recognised by an application and acted on specially) C0 control codes (STX, ENQ, ACK, DC4, EM, and RS) with 6 of the least used uppercase letter/diacritic combinations. While this may cause issues with some programs in handling VISCII text if they use those control codes, it creates fewer complications than either of the other two solutions. However, it leaves absolutely no space available for things other than accented letters such as symbols, superscripted numbers, curved quotes, proper dashes, etc.

VISCII, along with other Vietnamese-specific character sets, fell out of usage with the adoption of Unicode.

[edit] Code page layout

	.0	.1	.2	.3	.4	.5	.6	.7	.8	.9	.A	.B	.C	.D	.E	.F
0.	NUL 0	SOH 1	Ẳ 1EB2	ETX 3	EOT 4	Ẵ 1EB4	Ẫ 1EAA	BEL 7	BS 8	HT 9	LF A	VT B	FF C	CR D	SO E	SI F
1.	DLE 10	DC1 11	DC2 12	DC3 13	Ỷ 1EF6	NAC 15	SYN 16	ETB 17	CAN 18	Ỹ 1EF8	SUB 1A	ESC 1B	FS 1C	GS 1D	Ỵ 1EF4	US 1F
2.	20	! 21	" 22	# 23	$ 24	% 25	& 26	' 27	( 28	) 29	* 2A	+ 2B	, 2C	- 2D	. 2E	/ 2F
3.	0 30	1 31	2 32	3 33	4 34	5 35	6 36	7 37	8 38	9 39	: 3A	; 3B	< 3C	= 3D	> 3E	? 3F
4.	@ 40	A 41	B 42	C 43	D 44	E 45	F 46	G 47	H 48	I 49	J 4A	K 4B	L 4C	M 4D	N 4E	O 4F
5.	P 50	Q 51	R 52	S 53	T 54	U 55	V 56	W 57	X 58	Y 59	Z 5A	[ 5B	\ 5C	] 5D	^ 5E	_ 5F
6.	` 60	a 61	b 62	c 63	d 64	e 65	f 66	g 67	h 68	i 69	j 6A	k 6B	l 6C	m 6D	n 6E	o 6F
7.	p 70	q 71	r 72	s 73	t 74	u 75	v 76	w 77	x 78	y 79	z 7A	{ 7B	\| 7C	} 7D	~ 7E	DEL 7F
8.	Ạ 1EA0	Ắ 1EAE	Ằ 1EB0	Ặ 1EB6	Ấ 1EA4	Ầ 1EA6	Ẩ 1EA8	Ậ 1EAC	Ẽ 1EBC	Ẹ 1EB8	Ế 1EBE	Ề 1EC0	Ể 1EC2	Ễ 1EC4	Ệ 1EC6	Ố 1ED0
9.	Ồ 1ED2	Ổ 1ED4	Ỗ 1ED6	Ộ 1ED8	Ợ 1EE2	Ớ 1EDA	Ờ 1EDC	Ở 1EDE	Ị 1ECA	Ỏ 1ECE	Ọ 1ECC	Ỉ 1EC8	Ủ 1EE6	Ũ 168	Ụ 1EE4	Ỳ 1EF2
A.	Õ D5	ắ 1EAF	ằ 1EB1	ặ 1EB7	ấ 1EA5	ầ 1EA7	ẩ 1EA9	ậ 1EAD	ẽ 1EBD	ẹ 1EB9	ế 1EBF	ề 1EC1	ể 1EC3	ễ 1EC5	ệ 1EC7	ố 1ED1
B.	ồ 1ED3	ổ 1ED5	ỗ 1ED7	Ỡ 1EE0	Ơ 1A0	ộ 1ED9	ờ 1EDD	ở 1EDF	ị 1ECB	Ự 1EF0	Ứ 1EE8	Ừ 1EEA	Ử 1EEC	ơ 1A1	ớ 1EDB	Ư 1AF
C.	À C0	Á C1	Â C2	Ã C3	Ả 1EA2	Ă 102	ẳ 1EB3	ẵ 1EB5	È C8	É C9	Ê CA	Ẻ 1EBA	Ì CC	Í CD	Ĩ 128	ỳ 1EF3
D.	Đ 110	ứ 1EE9	Ò D2	Ó D3	Ô D4	ạ 1EA1	ỷ 1EF7	ừ 1EEB	ử 1EED	Ù D9	Ú DA	ỹ 1EF9	ỵ 1EF5	Ý DD	ỡ 1EE1	ư 1B0
E.	à E0	á E1	â E2	ã E3	ả 1EA3	ă 103	ữ 1EEF	ẫ 1EAB	è E8	é E9	ê EA	ẻ 1EBB	ì EC	í ED	ĩ 129	ỉ 1EC9
F.	đ 111	ự 1EF1	ò F2	ó F3	ô F4	õ F5	ỏ 1ECF	ọ 1ECD	ụ 1EE5	ù F9	ú FA	ũ 169	ủ 1EE7	ý FD	ợ 1EE3	Ữ 1EEE