ISO 646 Guide, Meaning , Facts, Information and Description

ISO 646 is an ISO standard that specifies a 7 bit character code from which several national standards are derived, the best known of which is ASCII. Since the portion of ISO 646 shared by all countries specified only the letters used in the English alphabet, other countries using the latin alphabet with extensions needed to create national variants of ISO 646 to be able to use their native languages. Since universal acceptance of the 8 bit byte did not exist at that time, the national characters had to be made fit within the constraints of 7 bits, meaning that some characters that appear in ASCII do not appear in other national variants of ISO 646.

Some national variants of ISO 646 are:

Code	National standard	Country
CA	CSA Z243.4	Canada
DE	DIN 66003	Germany
DK	DS 2089	Denmark
GB	BS 4730	Great Britain
HU	MSZ 7795.3	Hungary
JP	JIS X0201	Japan
MT		Malta
NO	NS 4551-1	Norway
SE	SEN 850200_B	Sweden
US	ANSI X3.4	United States
YU	JUS I.B1.002	former Yugoslavia

The specifics of the changes for some of these variants are given in this table:

Binary	Decimal	Hex	ASCII	DE	DK/NO	GB	HU	JP	MT	SE	YU
0010 0011	35	23	#	#	#	£	#	#	#	#	#
0010 0100	36	24	$	$	$	$	¤	$	$	¤	$
0100 0000	64	40	@	§	@	@	Á	@	@	@	Ž
0101 1011	91	5B	[	Ä	Æ	[	É	[	ġ	Ä	Š
0101 1100	92	5C	\\	Ö	Ø	\\	Ö	¥	ż	Ö	Đ
0101 1101	93	5D	]	Ü	Å	]	Ü	]	ħ	Å	Ć
0101 1110	94	5E	^	^	^	^	^	^	^	^	Č
0110 0000	96	60	`	`	`	`	á	`	ċ	`	ž
0111 1011	123	7B	{	ä	æ	{	é	{	Ġ	ä	š
0111 1100	124	7C	|	ö	ø	|	ö	|	Ż	ö	đ
0111 1101	125	7D	align="center"

| align="center"|ü | align="center"|å | align="center"|} | align="center"|ü | align="center"|} | align="center"|Ħ | align="center"|å | align="center"|ć |- |0111 1110 | align="center"|126 | align="center"|7E | align="center"|~ | align="center"|ß | align="center"|~ | align="center"|~ | align="center"|˝ | align="center"|‾ | align="center"|Ċ | align="center"|~ | align="center"|č |}

Later, when 8 bit characters sets gained more acceptance, ISO 8859-1, ISO 8859-2, and ISO 8859-3 became the preferred method of coding these variants.

Variants of ASCII that are not ISO 646

There are also some 7-bit character sets that are not officially part of the ISO 646 standard. Examples include:

• 7-bit Greek, ELOT 927. The Greek alphabet is mapped to positions 0x61-0x71 and 0x73-0x79, on top of the Latin lowercase letters. This mapping with the high bit set is ISO 8859-7.

• 7-bit Cyrillic, KOI-7 or Short KOI. The Cyrillic characters are mapped to positions 0x60-0x7E, on top of the Latin lowercase letters. Superseded by the KOI-8 variants.

• 7-bit Hebrew, SI 960. The Hebrew alphabet is mapped to positions 0x60-0x7A, on top of the lowercase Latin letters (and grave accent for aleph). This mapping with the high bit set, i.e. with the Hebrew letters in 0xE0-0xFA, is ISO 8859-8.

• 7-bit Arabic, ASMO 449. The Arabic alphabet is mapped to positions 0x41-0x5A and 0x60-0x6A, on top of both uppercase and lowercase Latin letters. This mapping with the high bit set is ISO 8859-6.

External links

• Zeichensatz nach ISO 646 (ASCII) (in German)
• http://aspell.net/charsets/iso646.html

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