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ASCII chart from a 1972 printer manual (b1 is the least significant bit)

ASCII ({{#invoke:IPAc-en|main}} ASS-kee), abbreviated from American Standard Code for Information Interchange,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> is a character-encoding scheme (the IANA prefers the name US-ASCII<ref name="IANA" />). ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many additional characters. ASCII was the most common character encoding on the World Wide Web until December 2007, when it was surpassed by UTF-8, which includes ASCII as a subset.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="utf-8-2008">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

ASCII developed from telegraphic codes. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6, 1960, with the first meeting of the American Standards Association's (ASA) X3.2 subcommittee. The first edition of the standard was published during 1963,<ref name="Brandel">{{#invoke:citation/CS1|citation |CitationClass=news }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> underwent a major revision during 1967,<ref>{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and experienced its most recent update during 1986.<ref>{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters.

Originally based on the English alphabet, ASCII encodes 128 specified characters into seven-bit binary integers as shown by the ASCII chart on the right.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The characters encoded are numbers 0 to 9, lowercase letters a to z, uppercase letters A to Z, basic punctuation symbols, control codes that originated with Teletype machines, and a space. For example, lowercase j would become binary 1101010 and decimal 106. ASCII includes definitions for 128 characters: 33 are non-printing control characters (many now obsolete)<ref name="Maini2007">{{#invoke:citation/CS1|citation |CitationClass=book }}</ref> that affect how text and space are processed<ref>International Organization for Standardization (December 1, 1975). "The set of control characters for ISO 646". Internet Assigned Numbers Authority Registry. Alternate U.S. version: [1]. Accessed 2008-04-14.</ref> and 95 printable characters, including the space (which is considered an invisible graphic<ref name="RFC20_1968">"RFC 20: ASCII format for Network Interchange", ANSI X3.4-1968, October 16, 1969.</ref><ref name="kenz">{{#invoke:citation/CS1|citation |CitationClass=book }}</ref>:223).


ASCII sections
Intro  History  ASCII control characters  ASCII printable characters  Aliases  Variants  Order  See also  Notes  References  Further reading  External links  

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