![]() With the adoption of electrical and electro-mechanical techniques these earliest codes were adapted to the new capabilities and limitations of the early machines. The earliest codes were based upon manual and hand-written encoding and cyphering systems, such as Bacon's cipher, Braille, International maritime signal flags, and the 4-digit encoding of Chinese characters for a Chinese telegraph code ( Hans Schjellerup, 1869). The history of character codes illustrates the evolving need for machine-mediated character-based symbolic information over a distance, using once-novel electrical means. 4 Character sets, character maps and code pages.Character encoding using internationally accepted standards permits worldwide interchange of text in electronic form. ![]() The low cost of digital representation of data in modern computer systems allows more elaborate character codes (such as Unicode) which represent most of the characters used in many written languages. The numerical values that make up a character encoding are known as " code points" and collectively comprise a "code space", a " code page", or a " character map".Įarly character codes associated with the optical or electrical telegraph could only represent a subset of the characters used in written languages, sometimes restricted to upper case letters, numerals and some punctuation only. Presence and absence of a hole represents 1 and 0, respectively for example, "W" is encoded as "1010111".Ĭharacter encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using digital computers. Punched tape with the word "Wikipedia" encoded in ASCII.
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