ASCII

ASCII1963-infobox-paths

US ASCII Control Character Symbols

ASCII (American Standard Code for Information Interchange) is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, although they support many additional characters.

History

ASCII was developed from telegraph 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 edition being published in 1963. The standard was revised in 1967 to define a 7-bit code, allowing for 128 different characters, including 33 control characters that affect how text is processed and 95 printable characters, including the space (which is considered an invisible graphic).

Character Set

The ASCII character set includes letters, digits, punctuation marks, and control characters. The characters are assigned numbers from 0 to 127. For example, the uppercase letter "A" is represented by the number 65. The ASCII table is divided into several sections:

- Control characters (codes 0–31 and 127): These are non-printable characters that control the flow of data in a text stream. Examples include the carriage return (CR), line feed (LF), and backspace (BS). - Printable characters (codes 32–126): This includes letters (both uppercase and lowercase), digits, punctuation marks, and a few miscellaneous symbols.

Extensions

Over time, various extensions to ASCII were created to accommodate characters used in non-English languages, as well as additional symbols. These extensions, such as ISO 8859-1 (Latin-1), use an 8th bit to provide 256 total characters, allowing for the inclusion of characters from many additional languages and special symbols.

Usage

ASCII is widely used in computing and telecommunications. It serves as the basis for file formats, data exchange, and network protocols. For example, the HTTP protocol for the World Wide Web uses ASCII to transfer data. Even though modern systems support a wide range of characters beyond ASCII, it remains a fundamental component of most text-processing applications.

See Also

• Character encoding
• Unicode
• ISO 8859-1

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