ISO/IEC 646

Template:Short description Template:For Template:Anchor Template:Use dmy dates Template:Infobox character encoding

ISO/IEC 646 Information technology — ISO 7-bit coded character set for information interchange, is an ISO/IEC standard in the field of character encoding. It is equivalent to the ECMA standard ECMA-6 and developed in cooperation with ASCII at least since 1964.<ref name="Ptak_2012"/><ref name="ISO_1964"/> The first version of ECMA-6 had been published in 1965,<ref name="ECMA-6_1985"/> based on work the ECMA's Technical Committee TC1 had carried out since December 1960.<ref name="ECMA-6_1985"/> The first edition of ISO/IEC 646 was published in 1973, and the most recent, third, edition in 1991.

ISO/IEC 646 specifies a 7-bit character code from which several national standards are derived. It allocates a set of 82 unique graphic characters to 7-bit code points, known as the invariant<ref name="Bodfish_2013"/> (INV) or basic character set,<ref name="ISO-IR-170"/> including letters of the ISO basic Latin alphabet, digits, and some common English punctuation. It leaves 12 code points to be allocated by conforming national standards for additional letters of Latin-based alphabets or other symbols.

It also defines the International Reference Version (IRV), including a full allocation of 94 graphic characters, to be used when a specific national version is not required. As of the 1991 edition of ISO/IEC 646, the IRV and ASCII are identical. Previous editions differed in only one or two code points.

HistoryEdit

File:ASCII1963-infobox-paths.svg

Early ASCII (ASA X3.4:1963)

ISO/IEC 646 and its predecessor ASCII (ASA X3.4) largely endorsed existing practice regarding character encodings in the telecommunications industry.

File:ASCII-infobox.svg

US-ASCII, or ISO/IEC 646:US

As ASCII did not provide a number of characters needed for languages other than English, a number of national variants were made that substituted some less-used characters with needed ones. Due to the incompatibility of the various national variants, an International Reference Version (IRV) of ISO/IEC 646 was introduced, in an attempt to at least restrict the replaced set to the same characters in all variants. The original version (ISO 646 IRV) differed from ASCII only in that code point 0x24, ASCII's dollar sign <syntaxhighlight lang="text" class="" style="" inline="1">$</syntaxhighlight> was replaced by the international currency symbol <syntaxhighlight lang="text" class="" style="" inline="1">¤</syntaxhighlight>. The final 1991 version of the code ISO/IEC 646:1991 is also known as ITU T.50, International Reference Alphabet or IRA, formerly International Alphabet No. 5 (IA5). This standard allows users to exercise the 12 variable characters (i.e., two alternative graphic characters and 10 national defined characters). Among these exercises, ISO 646:1991 IRV (International Reference Version) is explicitly defined and identical to ASCII.<ref name="Demchenko_2000"/>

The ISO/IEC 8859 series of standards governing 8-bit character encodings supersede the ISO/IEC 646 international standard and its national variants, by providing 96 additional characters with the additional bit and thus avoiding any substitution of ASCII codes. The ISO/IEC 10646 standard, directly related to Unicode, supersedes all of the ISO646 and ISO/IEC 8859 sets with one unified set of character encodings using a larger 21-bit value.

File:ISO-646-JP-paths.svg

ISO 646:JP

A legacy of ISO/IEC 646 is visible on Windows, where in many East Asian locales the backslash character used in filenames is rendered as ¥ or other characters such as ₩. Despite the fact that a different code for ¥ was available even on the original IBM PC's code page 437, and a separate double-byte code for ¥ is available in Shift JIS (although this often uses alternative mapping), so much text was created with the backslash code used for ¥ (due to Shift_JIS being officially based on ISO 646:JP, although Microsoft maps it as ASCII) that even modern Windows fonts have found it necessary to render the code that way. A similar situation exists with ₩ and EUC-KR. Another legacy is the existence of trigraphs in the C programming language.

Template:AnchorPublished standardsEdit

ECMA-6 (1965-04-30), first edition (withdrawn)<ref name="ECMA-6_1985"/>
ISO/R646-1967 (withdrawn),<ref name="Mackenzie_1980"/> or ECMA-6 (1967-06), second edition (withdrawn)<ref name="Mackenzie_1980"/><ref name="ECMA-6_1985"/>
ECMA-6 (1970-07), third edition (withdrawn)<ref name="ECMA-6_1985"/><ref name="ECMA-6_1973"/>
ISO 646:1972 (withdrawn), or ECMA-6 (1973-08), fourth edition (withdrawn)<ref name="ECMA-6_1985"/><ref name="ECMA-6_1973"/>
ISO 646:1983 (withdrawn),<ref name="ISO_646_1983"/> or ECMA-6 (1984-12, 1985-03), fifth edition (withdrawn)<ref name="ECMA-6_1985"/>
ITU-T Recommendation T.50 IA5 (1988-11-25) (withdrawn),<ref name="Salste_2016"/><ref name="ITU-CCITT_T50_1988">Template:Citation</ref> or ISO/IEC 646:1991 (in force),<ref name="ECMA-6_1991"/><ref name="ISO/IEC_646_1991"/> or ECMA-6 (1991-12, 1997-08), sixth edition (in force)<ref name="ECMA-6_1991"/>
ITU-T Recommendation T.50 IRA (1992-09-18) (in force)<ref name="Salste_2016">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref name="ITU-CCITT_T50_1993">Template:Citation</ref>

Code page layoutEdit

The following table shows the ISO/IEC 646:1991 International Reference Version character set. Each character is shown with its Unicode equivalent. Code points open for substitution in national variants are shown with a grey background. Yellow background indicates a character that, in some variants, could be combined with a previous character as a diacritic using the backspace character, which may affect glyph choice.

In addition to the invariant set restrictions, 0x23 is restricted to be either # or £ and 0x24 is restricted to be either $ or ¤.<ref name="ECMA-6_1991"/> However, these restrictions are not followed by all national variants.<ref name="ISO-IR-061" /><ref name="ISO-IR-057" />

Composite Graphic CharactersEdit

According to ISO/IEC 646, every graphic character must be a spacing character; that is, it must advance the character position forward. As a result, non-spacing combining characters are not permitted in any national version. This is in contrast to later standards such as ISO/IEC 2022 and ISO/IEC 10646 which permit or include combining characters.

Several spacing characters can be used as diacritical marks, when preceded or followed with a backspace C0 control to create accented letters, referred to as composite graphic characters in the standard. For example, the sequence <syntaxhighlight lang="text" class="" style="" inline="1">E</syntaxhighlight> <syntaxhighlight lang="text" class="" style="" inline="1"><BS></syntaxhighlight> <syntaxhighlight lang="text" class="" style="" inline="1">'</syntaxhighlight> may be used to image the character <syntaxhighlight lang="text" class="" style="" inline="1">É</syntaxhighlight>. This encoding method originated in the typewriter/teletype era when use of backspace would overstrike a glyph, and may be considered deprecated.

This method is attested in the code charts for the IRV, as well as the GB, FR1, CA, and CA2 national versions, which note that <syntaxhighlight lang="text" class="" style="" inline="1">"</syntaxhighlight>, <syntaxhighlight lang="text" class="" style="" inline="1">'</syntaxhighlight>, <syntaxhighlight lang="text" class="" style="" inline="1">,</syntaxhighlight>, and <syntaxhighlight lang="text" class="" style="" inline="1">^</syntaxhighlight> may behave as the diaeresis, acute accent, cedilla, and circumflex (rather than quotation marks, a comma, and an upward arrowhead), respectively, when preceded or followed by a backspace. The current PL-2002 standard explicitly directs the use of the backspace and apostrophe to form Polish letters with an acute accent. Some editions of ISO/IEC 646 also suggest that the solidus <syntaxhighlight lang="text" class="" style="" inline="1">/</syntaxhighlight> may be used with the equal sign Template:Char to compose the not equal sign, <syntaxhighlight lang="text" class="" style="" inline="1">≠</syntaxhighlight>, and that the underscore <syntaxhighlight lang="text" class="" style="" inline="1">_</syntaxhighlight> may be used to effect underlined text. The tilde character <syntaxhighlight lang="text" class="" style="" inline="1">~</syntaxhighlight> was similarly introduced as a diacritic <syntaxhighlight lang="text" class="" style="" inline="1">˜</syntaxhighlight>, although the standard is silent about its use.

Later, when wider character sets gained more acceptance, ISO/IEC 8859, vendor-specific character sets and eventually Unicode became the preferred methods of coding accented letters.

Variant codes and descriptionsEdit

ISO/IEC 646 national variantsEdit

Some national variants of ISO/IEC 646 are as follows:

Version CodeTemplate:Efn	ISO-IR	Registered Escape Sequence	Standard	Description
CA	121	ESC 2/8 7/7	CSA Z243.4-1985-1	Canada (No. 1 alternative, with "î") (French, classical) (Code page 1020<ref name="CP1020"/>)
CA2	122	ESC 2/8 7/8	CSA Z243.4-1985-2	Canada (No. 2 alternative, with "É") (French, reformed orthography)
CN	57<ref name="HP_PCLREF_2003"/>	ESC 2/8 5/4	GB/T 1988-80	People's Republic of China (Basic Latin)
CU	151	ESC 2/8 2/1 4/1	NC 99-10:81 / NC NC00-10:81	Cuba (Spanish)
DANO	9-1<ref name="Bemer_1980"/>	ESC 2/8 4/5<ref name="Bemer_1980"/>	NATS-DANO (SIS)	Norway and Denmark (journalistic texts). Invariant code point 0x22 is displayed as <syntaxhighlight lang="text" class="" style="" inline="1">«</syntaxhighlight>, (compare <syntaxhighlight lang="text" class="" style="" inline="1">"</syntaxhighlight> in the IRV). It is, however, still considered a double quotation mark.<ref name="ISO-IR-009-1"/> Accompanies SEFI (NATS-SEFI).
DE	21<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/11<ref name="Bemer_1980"/>	DIN 66003	Germany (German) (Code page 1011,<ref name="CP1011"/> 20106<ref name="MS_2014_CP201xx"/><ref name="WG_CP201xx"/><ref name="WU_CP20106"/>)
DK	—	—	DS 2089<ref name="DS2089_1974"/><ref name="Stroustrup_1994_DEC"/>	Denmark (Danish) (Code page 1017<ref name="CP1017"/>)
ES	17<ref name="Bemer_1980"/>	ESC 2/8 5/10<ref name="Bemer_1980"/>	Olivetti	Spanish (international) (Code page 1023<ref name="CP1023"/>)
ES2	85<ref name="HP_PCLREF_2003"/>	ESC 2/8 6/8	IBM	Spain (Basque, Castilian, Catalan, Galician) (Code page 1014<ref name="CP1014"/>)
FI	10<ref name="HP_PCLREF_2003"/>		SFS 4017	Finland (basic version) (Code page 1018<ref name="CP1018"/>)
FR	69<ref name="HP_PCLREF_2003"/>	ESC 2/8 6/6	AFNOR NF Z 62010-1982	France (French) (Code page 1010<ref name="CP1010"/>)
FR1	25<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 5/2<ref name="Bemer_1980"/>	AFNOR NF Z 62010-1973	France (obsolete since April 1985) (Code page 1104<ref name="CP1104"/>)
GB	4<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/1<ref name="Bemer_1980"/>	BS 4730	United Kingdom (English) (Code page 1013<ref name="CP1013"/>)
HU	86	ESC 2/8 6/9	MSZ 7795-3:1984	Hungary (Hungarian)
IE	207	ESC 2/8 2/1 4/3	I.S. 433:1996	Ireland (Irish)
INV	170	ESC 2/8 2/1 4/2	ISO 646:1983	Invariant subset
(IRV)	2<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/0<ref name="Bemer_1980"/>	ISO 646:1973	International Reference Version. 0x7E as an overline (ISO-IR-002).<ref name="ISO-IR-002"/>
	—	—	ISO 646:1983	International Reference Version. 0x7E as a tilde (Code page 1009,<ref name="CP1009"/> 20105<ref name="MS_2014_CP201xx"/><ref name="WG_CP201xx"/><ref name="WU_CP20105"/>).
	ISO 646:1991 International Reference Version matches the US variant (see below).
IS	—	—	—	Iceland (Icelandic) De facto standard, proposed in 1978 but never formally approved.
IT	15<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 5/9<ref name="Bemer_1980"/>	UNI 0204-70 / Olivetti?	Italian (Code page 1012<ref name="CP1012"/>)
JP	14<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/10<ref name="Bemer_1980"/>	JIS C 6220:1969-ro	Japan (Romaji) (Code page 895<ref name="CP895"/>). Also used as an 8-bit code with the corresponding Katakana supplementary set.
JP-OCR-B	92	ESC 2/8 6/14	JIS C 6229-1984-b	Japan (OCR-B)
KR	—	—	KS C 5636-1989	South Korea
MT	—	—	?	Malta (Maltese, English)
NL	—	—	IBM	Netherlands (Dutch) (Code page 1019<ref name="CP1019"/>)
NO	60<ref name="HP_PCLREF_2003"/>	ESC 2/8 6/0	NS 4551 version 1<ref name="HP_PCLREF_2003"/>	Norway (Code page 1016<ref name="CP1016"/>)
NO2	61<ref name="HP_PCLREF_2003"/>	ESC 2/8 6/1	NS 4551 version 2<ref name="HP_PCLREF_2003"/>	Norway (obsolete since June 1987) (Code page 20108<ref name="MS_2014_CP201xx"/><ref name="WG_CP201xx"/><ref name="WU_CP20108"/>)
PL-2002	—	—	PN-I-10050:2002<ref name="PN-I-10050"/>	Poland (current as of 2025) Set for writing Polish. Includes the Euro sign.
PL-ZU0	—	—	PN-T-42109-02:1984<ref name="PN-T-42109-02"/>	Poland (withdrawn in 2000) Set named "ZU0" for writing Polish.
PT	16<ref name="HP_PCLREF_2003"/>	ESC 2/8 4/12	Olivetti	Portuguese (international)
PT2	84<ref name="HP_PCLREF_2003"/>	ESC 2/8 6/7	IBM	Portugal (Portuguese, Spanish) (Code page 1015<ref name="CP1015"/>)
SE	10<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/7<ref name="Bemer_1980"/>	SEN 850200 Annex B, SIS 63 61 27	Sweden (basic Swedish) (Code page 1018,<ref name="CP1018"/> D47)
SE2	11<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/8<ref name="Bemer_1980"/>	SEN 850200 Annex C, SIS 63 61 27	Sweden (extended Swedish for names) (Code page 20107,<ref name="MS_2014_CP201xx"/><ref name="WG_CP201xx"/><ref name="WU_CP20107"/> E47)
SEFI	8-1<ref name="Bemer_1980"/>	ESC 2/8 4/3<ref name="Bemer_1980"/>	NATS-SEFI (SIS)	Sweden and Finland (journalistic texts). Accompanies DANO (NATS-DANO).
T.61-7bit	102	ESC 2/8 7/5	ITU/CCITT T.61 Recommendation	International (Teletex). Also used with the corresponding supplementary set as an 8-bit code.
TW	—		CNS 5205-1996	Republic of China (Taiwan)
US / (IRV)	6<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/2<ref name="Bemer_1980"/>	ANSI X3.4-1968 and ISO 646:1983 (also IRV in ISO/IEC 646:1991)	United States (ASCII, Code page 367,<ref name="CP367"/> 20127<ref name="MS_2014_CP201xx"/><ref name="WG_CP201xx"/><ref name="WU_CP20127"/>)
YU	141	ESC 2/8 7/10	JUS I.B1.002 (YUSCII)	former Yugoslavia (Croatian, Slovene, Serbian, Bosnian)
INIS	49	ESC 2/8 5/7	INIS (IAEA)	ISO 646 IRV subset

National derivativesEdit

Some national character sets also exist which are based on ISO/IEC 646 but do not strictly follow its invariant set (see also § Derivatives for other alphabets):

Character set	ISO-IR	Registered Escape Sequence	Standard	Description
BS_viewdata	47	ESC 2/8 5/6	British Post Office	Viewdata and Teletext. Viewdata square (⌗) substituted for normally invariant underscore (_) which cannot be displayed on the target hardware.<ref name="ISO-IR-047"/> This is actually the encoding of Microsoft's WST_Engl.
GR / greek7	88	ESC 2/8 6/10	HOS ELOT 927	Greece (withdrawn in November 1986). Uses Greek letters in place of Roman ones<ref name="ISO-IR-088"/> and hence is not strictly speaking an ISO 646 variant.
greek7-old	18	ESC 2/8 5/11	?	Greek graphic set. Similar in concept to greek7, but uses a different mapping of letters. Also, the upper case follows the lower case.
Latin-Greek	19	ESC 2/8 5/12	?	Latin-Greek combined graphics (capitals only). Follows greek7-old, but includes Latin capitals without modification, and Greek capitals over the Latin lower case.
Latin-Greek-1	27<ref name="Bemer_1980"/>	ESC 2/8 5/5<ref name="Bemer_1980"/>	Honeywell-Bull	Latin-Greek mixed graphics (Greek capitals only).<ref name="Bemer_1980"/> Visually unifies Greek capitals with Latin capitals where possible, and adds the remaining Greek capitals. Unlike the other Greek versions, all Basic Latin letters remain intact. Replaces invariant punctuation as well as national characters, however,<ref name="ISO-IR-027"/> and hence is still not strictly speaking an ISO 646 variant.
CH7DEC	—	—	DEC	Switzerland (French, German) (Code page 1021<ref name="CP1021"/>) Invariant code point 0x5F is changed from <syntaxhighlight lang="text" class="" style="" inline="1">_</syntaxhighlight> to <syntaxhighlight lang="text" class="" style="" inline="1">è</syntaxhighlight>. Is a DEC NRCS variant, closely related to ISO 646, but lacks a fully ISO 646 compliant equivalent.
PL-ZU1	—	—	PN-⁠T⁠-⁠42109-02<ref name="PN-T-42109-02"/>	Poland (withdrawn in 2000) Set named "ZU1" intended for use with ODRA 1300 mainframes. These use the same character set as ICT 1900 mainframes, which was based on a 1963 proposed version of ASCII prior to its standardization.
TR7DEC	—	—	DEC	A 7-bit set for writing Turkish, available on some DEC terminals and printing equipment.<ref name="tr7dec"/> It is not referred to as a NRCS in DEC's documentation, but is mentioned separately. Invariant code point 0x21 is changed from <syntaxhighlight lang="text" class="" style="" inline="1">!</syntaxhighlight> to <syntaxhighlight lang="text" class="" style="" inline="1">ı</syntaxhighlight>, and 0x26 is changed from <syntaxhighlight lang="text" class="" style="" inline="1">&</syntaxhighlight> to <syntaxhighlight lang="text" class="" style="" inline="1">ğ</syntaxhighlight>.

Control charactersEdit

All the variants listed above are solely graphical character sets, and are to be used with a C0 control character set such as listed in the following table:

ISO-IR	ISO ESC	Description
1<ref name="Bemer_1980"/>	ESC 2/1 4/0<ref name="Bemer_1980"/>	ISO 646 controls<ref name="Bemer_1980"/> ("ASCII controls")
7<ref name="Bemer_1980"/>	ESC 2/1 4/1<ref name="Bemer_1980"/>	Scandinavian newspaper (NATS) controls<ref name="Bemer_1980"/>
26<ref name="Bemer_1980"/>	ESC 2/1 4/3<ref name="Bemer_1980"/>	IPTC controls<ref name="Bemer_1980"/>

Associated supplementary character setsEdit

The following table lists supplementary graphical character sets defined by the same standard as specific ISO/IEC 646 variants. These would be selected by using a mechanism such as shift out or the NATS super shift (single shift),<ref name="ISO-IR-007"/> or by setting the eighth bit in environments where one was available:

ISO-IR	ISO/IEC ESC	National Standard	Description
8-2<ref name="Bemer_1980"/>	ESC 2/8 4/4<ref name="Bemer_1980"/>	NATS-SEFI-ADD	Supplementary code used with NATS-SEFI.
9-2<ref name="Bemer_1980"/>	ESC 2/8 4/6<ref name="Bemer_1980"/>	NATS-DANO-ADD	Supplementary code used with NATS-DANO.
13<ref name="Bemer_1980"/><ref name="HP_PCLREF_2003"/>	ESC 2/8 4/9<ref name="Bemer_1980"/>	JIS C 6220:1969-jp	Katakana, used as a supplementary code with ISO-646-JP.
103	ESC 2/8 7/6	ITU/CCITT T.61 Recommendation, Supplementary Set	Supplementary code used with T.61.
—	—	PN⁠-⁠T⁠-⁠42109-03:1986<ref name="PN-T-42109-03"/>	(withdrawn in 2000) Set named "ZU2" for writing Polish. Contains all letters used in Polish, including the uppercase letters missing from ZU0. Intended to be used as a supplementary set with either the IRV, ZU0, or ZU1 as the primary set.

Template:AnchorVariant comparison chartEdit

The specifics of the changes for some of these variants are given in the following table. Character assignments unchanged across all listed variants (i.e. which remain the same as ASCII) are not shown.

For ease of comparison, variants detailed include national variants of ISO/IEC 646, DEC's closely related National Replacement Character Set (NRCS) series used on VT200 terminals, the related European World System Teletext encoding series defined in ETS 300 706, and a few other closely related encodings based on ISO/IEC 646. Individual code charts are linked from the second column. The cells with non-white background emphasize the differences from US-ASCII (also the Basic Latin subset of ISO/IEC 10646 and Unicode).

Version CodeTemplate:Efn	Code Chart	Characters for each ISO 646 / NRCS compatible or derived charset
US / IRV (1991)	ISO-IR-006<ref name="ISO-IR-006">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	@	[	\	]	^	_	`	{	\|	}	~
Older International Reference Versions
IRV (1973)	ISO-IR-002<ref name="ISO-IR-002"/>	!	"	#	¤	&	:	?	@	[	\	]	^	_	`	{	\|	}	‾
IRV (1983)	citation	CitationClass=web }}</ref>	!	"	#	¤	&	:	?	@	[	\	]	^	_	`	{	\|	}	~
Invariant and other IRV subsets
INV	ISO-IR-170<ref name="ISO-IR-170">Template:Cite iso-ir</ref>	!	"			&	:	?						_
INV (NRCS)Template:Efn	---	!	"		$	&	:	?
INV (Teletext)Template:Efn	ETS WST<ref name="etslatininv">Template:Citation</ref>	!	"			&	:	?
INIS SubsetTemplate:Efn	ISO-IR-049<ref name="ISO-IR-049">Template:Cite iso-ir</ref>				$		:			[		]					\|
T.61	ISO-IR-102<ref name="ISO-IR-102">Template:Cite iso-ir</ref>	!	"	#	¤	&	:	?	@	[		]		_			\|
East Asian
JP	ISO-IR-014<ref name="ISO-IR-014">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	@	[	¥	]	^	_	`	{	\|	}	‾
JP-OCR-B	ISO-IR-092<ref name="ISO-IR-092">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	@	[	¥	]	^	_		{	\|	}
KR	(KS X 1003)<ref name="lundeiso646" />	!	"	#	$	&	:	?	@	[	₩	]	^	_	`	{	\|	}	‾
CN	ISO-IR-057<ref name="ISO-IR-057">Template:Cite iso-ir</ref>	!	"	#	¥	&	:	?	@	[	\	]	^	_	`	{	\|	}	‾
TW	(CNS 5205)<ref name="lundeiso646">Template:Cite book</ref>	!	"	#	$	&	:	?	@	[	\	]	^	_	`	{	\|	}	‾
British and Irish
GB	ISO-IR-004<ref name="ISO-IR-004">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	@	[	\	]	^	_	`	{	\|	}	‾
GB (NRCS)	citation	CitationClass=web }}</ref>	!	"	£	$	&	:	?	@	[	\	]	^	_	`	{	\|	}	~
ViewdataTemplate:Efn Template:Efn	ISO-IR-047<ref name="ISO-IR-047"/>	!	"	£	$	&	:	?	@	←	½	→	↑	⌗	―	¼	‖	¾	÷
IE	ISO-IR-207<ref name="ISO-IR-207">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	Ó	É	Í	Ú	Á	_	ó	é	í	ú	á
Italophone or Francophone
ITTemplate:Efn	ISO-IR-015<ref name="ISO-IR-015">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	§	°	ç	é	^	_	ù	à	ò	è	ì
IT (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	£	$	&	:	?	é	°	ç	→	↑	⌗	ù	à	ò	è	ì
FR	ISO-IR-069<ref name="ISO-IR-069">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	à	°	ç	§	^	_	µ	é	ù	è	¨
FR1 Template:Efn	ISO-IR-025<ref name="ISO-IR-025">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	à	°	ç	§	^	_	`	é	ù	è	¨
FR Teletext Template:Efn	ETS WST<ref name="ets300706">Template:Citation</ref>	!	"	é	ï	&	:	?	à	ë	ê	ù	î	⌗	è	â	ô	û	ç
CATemplate:Efn	ISO-IR-121<ref name="ISO-IR-121">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	à	â	ç	ê	î	_	ô	é	ù	è	û
CA2	ISO-IR-122<ref name="ISO-IR-122">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	à	â	ç	ê	É	_	ô	é	ù	è	û
Francophone-Germanophone
CH (NRCS)Template:Efn	citation	CitationClass=web }}</ref>	!	"	ù	$	&	:	?	à	é	ç	ê	î	è	ô	ä	ö	ü	û
Germanophone
DETemplate:Efn Template:Efn	ISO-IR-021<ref name="ISO-IR-021">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	§	Ä	Ö	Ü	^	_	`	ä	ö	ü	ß
Nordic (Eastern) and Baltic
FI / SE	ISO-IR-010<ref name="ISO-IR-010">Template:Cite iso-ir</ref>	!	"	#	¤	&	:	?	@	Ä	Ö	Å	^	_	`	ä	ö	å	‾
SE2Template:Efn	ISO-IR-011<ref name="ISO-IR-011">Template:Cite iso-ir</ref>	!	"	#	¤	&	:	?	É	Ä	Ö	Å	Ü	_	é	ä	ö	å	ü
SE (NRCS)	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	É	Ä	Ö	Å	Ü	_	é	ä	ö	å	ü
FI (NRCS)	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	@	Ä	Ö	Å	Ü	_	é	ä	ö	å	ü
SEFI (NATS)Template:Efn	ISO-IR-008-1<ref name="ISO-IR-008-1">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?		Ä	Ö	Å	■	_		ä	ö	å	–
EE (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	õ	&	:	?	Š	Ä	Ö	Ž	Ü	Õ	š	ä	ö	ž	ü
LV / LT (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	$	&	:	?	Š	ė	ę	Ž	č	ū	š	ą	ų	ž	į
Nordic (Western)
DK	citation	CitationClass=web }}</ref>	!	"	#	¤	&	:	?	@	Æ	Ø	Å	Ü	_	`	æ	ø	å	ü
DK/NO (NRCS)	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	Ä	Æ	Ø	Å	Ü	_	ä	æ	ø	å	ü
DK/NO-alt (NRCS)	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	@	Æ	Ø	Å	^	_	`	æ	ø	å	~
NO	ISO-IR-060<ref name="ISO-IR-060">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	@	Æ	Ø	Å	^	_	`	æ	ø	å	‾
NO2	ISO-IR-061<ref name="ISO-IR-061">Template:Cite iso-ir</ref>	!	"	§	$	&	:	?	@	Æ	Ø	Å	^	_	`	æ	ø	å	\|
DANO (NATS)Template:Efn Template:Efn	ISO-IR-009-1<ref name="ISO-IR-009-1"/>	!	«	»	$	&	:	?		Æ	Ø	Å	■	_		æ	ø	å	–
IS	[proposed]<ref name="tolvumal">Template:Cite magazine</ref>	!	"	#	¤	&	:	?	Ð	Þ	´ Template:Efn	Æ	Ö	_	ð	þ	´ Template:Efn	æ	ö
Hispanophone
ESTemplate:Efn	ISO-IR-017<ref name="ISO-IR-017">Template:Cite iso-ir</ref>	!	"	£	$	&	:	?	§	¡	Ñ	¿	^	_	`	°	ñ	ç	~
ES2	ISO-IR-085<ref name="ISO-IR-085">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	·	¡	Ñ	Ç	¿	_	`	´	ñ	ç	¨
CU	ISO-IR-151<ref name="ISO-IR-151">Template:Cite iso-ir</ref>	!	"	#	¤	&	:	?	@	¡	Ñ	]	¿	_	`	´	ñ	[	¨
Hispanophone-Lusophone
ES/PT Teletext Template:Efn	ETS WST<ref name="ets300706"/>	!	"	ç	$	&	:	?	¡	á	é	í	ó	ú	¿	ü	ñ	è	à
Lusophone
PT	ISO-IR-016<ref name="ISO-IR-016">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	§	Ã	Ç	Õ	^	_	`	ã	ç	õ	°
PT2	ISO-IR-084<ref name="ISO-IR-084">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	´	Ã	Ç	Õ	^	_	`	ã	ç	õ	~
PT (NRCS)	---	!	"	#	$	&	:	?	@	Ã	Ç	Õ	^	_	`	ã	ç	õ	~
Greek
Latin-GR mixedTemplate:Efn	ISO-IR-027<ref name="ISO-IR-027"/>	Ξ	"	Γ	¤	&	Ψ	Π	Δ	Ω	Θ	Φ	Λ	Σ	`	{	\|	}	‾
ISO-IR-088 (GR / ELOT 927), ISO-IR-018 and ISO-IR-019 replace Roman letters with Greek letters and are detailed in a separate chart.
Slavic (Latin script)
YU	ISO-IR-141<ref name="ISO-IR-141">Template:Cite iso-ir</ref>	!	"	#	$	&	:	?	Ž	Š	Đ	Ć	Č	_	ž	š	đ	ć	č
YU Teletext Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	Ë	&	:	?	Č	Ć	Ž	Đ	Š	ë	č	ć	ž	đ	š
YU-alt Teletext Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	$	&	:	?	Č	Ć	Ž	Đ	Š	ë	č	ć	ž	đ	š
CS/CZ/SK (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	ů	&	:	?	č	ť	ž	ý	í	ř	é	á	ě	ú	š
PL-2002	PN⁠-⁠I-⁠10050<ref name="PN-I-10050"/>	!	"	#	$	&	:	?	@	Ą	Ę	Ł	Ż	_	€	ą	ę	ł	ż
PL-ZU0	PN⁠-⁠T⁠-⁠42109-02<ref name="PN-T-42109-02"/>	!	"	#	¤	&	:	?	ę	ź	Ł	ń	ś	_	ą	ó	ł	ż	ć
PL-ZU1Template:Efn	PN⁠-⁠T⁠-⁠42109-02<ref name="PN-T-42109-02"/>	!	"	#	£	&	:	?	@	[	$	]	↑	←	_
PL-ZU2Template:Efn Template:Efn	PN⁠-⁠T⁠-⁠42109-03<ref name="PN-T-42109-03"/>	!	"	Ę	Ć	Ż	:	?	ę	ź	Ł	ń	ś	_	ą	ó	ł	ż	ć
PL Teletext Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	ń	&	:	?	ą	Ƶ	Ś	Ł	ć	ó	ę	ż	ś	ł	ź
Adaptations for the Cyrillic script replace Roman letters and are detailed in a separate chart
Other
NL	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	@	[	\	]	^	_	`	{	\|	}	‾
NL NRCS	citation	CitationClass=web }}</ref>	!	"	£	$	&	:	?	¾	ĳ	½	\|	^	_	`	¨	ƒ	¼	´
HU	ISO-IR-086<ref name="ISO-IR-086">Template:Cite iso-ir</ref>	!	"	#	¤	&	:	?	Á	É	Ö	Ü	^	_	á	é	ö	ü	˝
MT	citation	CitationClass=web }}</ref>	!	"	#	$	&	:	?	@	ġ	ż	ħ	^	_	ċ	Ġ	Ż	Ħ	Ċ
RO (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	#	¤	&	:	?	Ţ	Â	Ş	Ă	Î	ı	ţ	â	ş	ă	î
TR (DEC)Template:Efn	DEC<ref name="tr7dec">Template:Cite manual</ref>	ı	"	#	$	ğ	:	?	İ	Ş	Ö	Ç	Ü	_	Ğ	ş	ö	ç	ü
TR (Teletext)Template:Efn	ETS WST<ref name="ets300706"/>	!	"	TL	ğ	&	:	?	İ	Ş	Ö	Ç	Ü	Ğ	ı	ş	ö	ç	ü

Template:Notelist

Related encoding familiesEdit

National Replacement Character SetEdit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} The National Replacement Character Set (NRCS) is a family of 7-bit encodings introduced in 1983 by DEC with the VT200 series of computer terminals. It is closely related to ISO/IEC 646, being based on a similar invariant subset of ASCII, differing in retaining <syntaxhighlight lang="text" class="" style="" inline="1">$</syntaxhighlight> as invariant but not <syntaxhighlight lang="text" class="" style="" inline="1">_</syntaxhighlight>. All NRCS variants except Swiss retain <syntaxhighlight lang="text" class="" style="" inline="1">_</syntaxhighlight> in its ASCII position, and are therefore in conformance with ISO/IEC 646. Several NRCS variants are identical to ISO/IEC 646 variants, and others are very similar, with the exception of the Dutch variant.

World System TeletextEdit

Template:Further The European telecommunications standard ETS 300 706, "Enhanced Teletext specification", defines Latin, Greek, Cyrillic, Arabic, and Hebrew code sets with several national variants for both Latin and Cyrillic.<ref name="ets300706"/> Like NRCS and ISO/IEC 646, within the Latin variants, the family of encodings known as the G0 set are based on a similar invariant subset of ASCII, but do not retain either <syntaxhighlight lang="text" class="" style="" inline="1">$</syntaxhighlight> nor <syntaxhighlight lang="text" class="" style="" inline="1">_</syntaxhighlight> as invariant. Unlike NRCS, variants often differ considerably from corresponding national ISO/IEC 646 variants.

HPEdit

HP has code page 1054, which adds the medium shade (▒, U+2592) at 0x7F.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Code page 1052 replaces a few ASCII characters from code page 1054.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Template:AnchorDerivatives for other alphabetsEdit

Template:See also

Some 7-bit character sets for non-Latin alphabets are derived from the ISO/IEC 646 standard: these do not themselves constitute ISO/IEC 646 due to not following its invariant code points (often replacing the letters of at least one case), due to supporting differing alphabets which the set of national code points provide insufficient encoding space for. Examples include:

7-bit Turkmen (ISO-IR-230).<ref name="ISO-IR-230">Template:Cite iso-ir</ref>
7-bit Greek.
- In ELOT 927 (ISO-IR-088),<ref name="ISO-IR-088"/> the Greek alphabet is mapped in alphabetical order (except for the final-sigma) to positions 0x61–0x71 and 0x73–0x79, on top of the Latin lowercase letters.
- ISO-IR-018<ref name="ISO-IR-018">Template:Cite iso-ir</ref> maps the Greek alphabet over both letter cases using a different scheme (not in alphabetical order, but trying where possible to match Greek letters over Roman letters which correspond in some sense), and ISO-IR-019<ref name="ISO-IR-019">Template:Cite iso-ir</ref> maps the Greek uppercase alphabet over the Latin lowercase letters using the same scheme as ISO-IR-018.
- The lower half of the Symbol font character encoding<ref name="Apple_Symbol">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> uses its own scheme for mapping Greek letters of both cases over the ASCII Roman letters, also trying to map Greek letters over Roman letters which correspond in some sense, but making different decisions in this regard (see chart below). It also replaces invariant code points 0x22 and 0x27 and five national code points with mathematical symbols. Although not intended for use in typesetting Greek prose, it is sometimes used for that purpose.

- ISO-IR-027<ref name="ISO-IR-027"/> (detailed in the chart above rather than below) includes the Latin alphabet unchanged, but adds some Greek capital letters which cannot be represented with Latin-script homoglyphs; while it is explicitly based on ISO/IEC 646, some of these are mapped to code points which are invariant in ISO/IEC 646 (0x21, 0x3A, and 0x3F), and it is therefore not a true ISO/IEC 646 variant.
- The World System Teletext encoding for Greek uses yet another scheme of mapping Greek letters in alphabetical order over the ASCII letters of both cases, notably including several letters with diacritics.<ref name="etsgreek">Template:Citation</ref>
7-bit Cyrillic
- KOI-7 or Short KOI, used for Russian. The Cyrillic characters are mapped to positions 0x60–0x7E, on top of the Latin lowercase letters, matching homologous letters where possible (where в is mapped to w, not v). Superseded by the KOI-8 variants.
- SRPSCII and MAKSCII, Cyrillic variants of YUSCII (the Latin variant is YU/ISO-IR-141 in the chart above), used for Serbian and Macedonian respectively. Largely homologous to the Latin variant of YUSCII (following Serbian digraphia rules), except for Љ (lj), Њ (nj), Џ (dž), and ѕ (dz), which correspond to digraphs in Latin-script orthography, and are mapped over letters which are not used in Serbian or Macedonian (q, w, x, y).
- The G0 sets for the World System Teletext encodings for Russian/Bulgarian<ref name="etsrussia">Template:Citation</ref> and Ukrainian<ref name="etsukraine">Template:Citation</ref> use G0 sets similar to KOI-7 with some modifications. The corresponding G0 set for Serbian CyrillicTemplate:Efn<ref name="etsserbia">Template:Citation</ref> uses a scheme based on the Teletext encoding for Latin-script Serbo-Croatian and Slovene, as opposed to the significantly different YUSCII.
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). 7-bit Hebrew was always stored in visual order. This mapping with the high bit set, i.e. with the Hebrew letters in 0xE0–0xFA, is ISO/IEC 8859-8. The World System Teletext encoding for Hebrew uses the same letter mappings, but uses BS_Viewdata as its base encoding (whereas SI 960 uses US-ASCII) and includes a shekel sign at 0x7B.
7-bit Arabic, ASMO 449 (ISO-IR-089).<ref name="ISO-IR-089">Template:Cite iso-ir</ref> The Arabic alphabet is mapped to positions 0x41–0x5A and 0x60–0x6A, on top of both uppercase and lowercase Latin letters.

A comparison of some of these encodings is below. Only one case is shown, except in instances where the cases are mapped to different letters. In such instances, the mapping with the smallest code is shown first. Possible transcriptions are given for some letters; where this is omitted, the letter can be considered to correspond to the Roman one which it is mapped over.

English (ASCII)	Cyrillic alphabets						Greek alphabet				Hebrew
	Semi-transliterative								Naturally ordered
	Russian (KOI-7)	Russian, Bulgarian (WST RU/BG)	Ukrainian (WST UKR)	Serbian (SRPSCII)	Macedonian (MAKSCII)	Serbian, MacedonianTemplate:Efn (WST SRP)	Greek (Symbol)	Greek (IR-18<ref name="ISO-IR-018" />)	Greek (ELOT 927)	Greek (WST EL)	Hebrew (SI 960)
@ `	Ю (ju/yu)	Ю (ju/yu)	Ю (ju/yu)	Ж (ž)	Ж (ž)	Ч (č)	≅ ‾	´ `	@ `	ΐ ΰ	א (ʾ/ʔ)
A	А	А (a/á)	А	А	А	А	Α	Α	Α	Α	ב (b)
B	Б	Б	Б	Б	Б	Б	Β	Β	Β	Β	ג (g)
C	Ц (c/ts)	Ц (c/ts)	Ц (c/ts)	Ц (c/ts)	Ц (c/ts)	Ц (c/ts)	Χ (ch/kh)	Ψ (ps)	Γ (g)	Γ (g)	ד (d)
D	Д	Д	Д	Д	Д	Д	Δ	Δ	Δ	Δ	ה (h)
E	Е (je/ye)	Е (je/ye)	Е (e)	Е (e)	Е (e)	Е (e)	Ε	Ε	Ε	Ε	וTemplate:Popdf (w)
F	Ф	Ф	Ф	Ф	Ф	Ф	Φ (ph/f)	Φ (ph/f)	Ζ (z)	Ζ (z)	ז (z)
G	Г	Г	Г	Г	Г	Γ	Γ	Γ	Η (ē)	Η (ē)	ח (ch/kh)
H	Х (h/kh/ch)	Х (h/kh/ch)	Х (h/kh/ch)	Х (h/kh/ch)	Х (h/kh/ch)	Х (h/kh/ch)	Η (ē)	Η (ē)	Θ (th)	Θ (th)	ט (tt)
I	И	И	И (y)	И	И	И	Ι	Ι	Ι	Ι	י (j/y)
J	Й (j/y)	Й (j/y)	Й (j/y)	Ј (j/y)	Ј (j/y)	Ј (j/y)	ϑ (th) ϕ (ph/f)	Ξ (x/ks)		Κ (k)	ך (k final)
K	К	К	К	К	К	К	Κ	Κ	Κ	Λ (l)	כ
L	Л	Л	Л	Л	Л	Л	Λ	Λ	Λ	Μ (m)	ל
M	М	М	М	М	М	М	Μ	Μ	Μ	Ν (n)	ם (m final)
N	Н	Н	Н	Н	Н	Н	Ν	Ν	Ν	Ξ (x/ks)	מ (m)
O	О	О	О	О	О	О	Ο	Ο	Ξ (x/ks)	Ο	ן (n final)
P	П	П	П	П	П	П	Π	Π	Ο (o)	Π	נ (n)
Q	Я (ja/ya)	Я (ja/ya)	Я (ja/ya)	Љ (lj/ly)	Љ (lj/ly)	Ќ (Ḱ/kj)	Θ (th)	ͺ (i)	Π (p)	Ρ (r)	ס (s)
R	Р	Р	Р	Р	Р	Р	Ρ	Ρ	Ρ	ʹ ς (s final)	ע (Template:Asper/ŋ)
S	С	С	С	С	С	С	Σ	Σ	Σ	Σ	ף (p final)
T	Т	Т	Т	Т	Т	Т	Τ	Τ	Τ	Τ	פ (p)
U	У	У	У	У	У	У	Υ	Θ (th)	Υ	Υ	ץ (ṣ/ts final)
V	Ж (ž)	Ж (ž)	Ж (ž)	В	В	В	ς (s final) ϖ (p)	Ω (ō)	Φ (f/ph)	Φ (f/ph)	צ (ṣ/ts)
W	В (v)	В (v)	В (v)	Њ (nj/ny/ñ)	Њ (nj/ny/ñ)	Ѓ (ǵ/gj)	Ω (ō)	ς (s final)	ς (s final)	Χ (ch/kh)	ק (q)
X	Ь (’)	Ь (’)	Ь (’)	Џ (dž)	Џ (dž)	Љ (lj/ly)	Ξ	Χ (ch/kh)	Χ (ch/kh)	Ψ (ps)	ר (r)
Y	Ы (y/ı)	Ъ (″/ǎ/ŭ)	І (i)	Ѕ (dz)	Ѕ (dz)	Њ (nj/ny/ñ)	Ψ (ps)	Υ (u)	Ψ (ps)	Ω (ō)	ש (š/sh)
Z	З	З	З	З	З	З	Ζ	Ζ	Ω (ō)	Ϊ	ת (t)
[ {	Ш (š/sh)	Ш (š/sh)	Ш (š/sh)	Ш (š/sh)	Ш (š/sh)	Ћ (ć)	[ {	῏ ῟	[ {	Ϋ	[ {
\ Template:Pipe	Э (e)	Э (e)	Є (je/ye)	Ђ (đ/dj)	Ѓ (ǵ/gj)	Ж (ž)	∴ Template:Pipe	᾿ ῾ (h)	\ Template:Pipe	ά ό	\ Template:Pipe
] }	Щ (šč)	Щ (šč)	Щ (šč)	Ћ (ć)	Ќ (Ḱ/kj)	Ђ (đ/dj)	] }	῎ ῞	] }	έ ύ	] }
^ ~	Ч (č)	Ч (č)	Ч (č)	Ч (č)	Ч (č)	Ш (š/sh)	⊥ ~	˜ ¨	^ ‾	ή ώ	^ ‾
_	Ъ (″)	Ы (y/ı)	Ї (ji/yi)	_	_	Џ (dž)	_	_	_	ί	_

FootnotesEdit

Template:Notelist

ReferencesEdit

Template:Reflist

External linksEdit

ISO/IEC 646:1991 Information technology — ISO 7-bit coded character set for information interchange
Zeichensatz nach ISO 646 (ASCII) (in German)
History at GNU Aspell website
ISO646 Character Tables Character Tables by Koichi Yasuoka (安岡孝) (see Domestic ISO646 Character Tables and Quasi-ISO646 Character Tables)
Turkish Text Deasciifier a tool (based on statistical pentagram analysis of the Turkish language) which reverts an ASCII'fied Turkish text by determining the appropriate (but ambiguous) diacritics normally needed in Turkish but missing in the US-ASCII set.

Template:List of International Electrotechnical Commission standards Template:Character encoding Template:Ecma International Standards Template:ISO standards Template:Latin alphabet

ISO/IEC 646

Contents

HistoryEdit

Template:AnchorPublished standardsEdit

Code page layoutEdit

Composite Graphic CharactersEdit

Variant codes and descriptionsEdit

ISO/IEC 646 national variantsEdit

National derivativesEdit

Control charactersEdit

Associated supplementary character setsEdit

Template:AnchorVariant comparison chartEdit

Related encoding familiesEdit

National Replacement Character SetEdit

World System TeletextEdit

HPEdit

Template:AnchorDerivatives for other alphabetsEdit

See alsoEdit

FootnotesEdit

ReferencesEdit

Further readingEdit

External linksEdit