American Standard Code for Information Interchange (ASCII), is a character encoding based on the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that work with text. Most modern character encodings — which support many more characters than did the original — have a historical basis in ASCII. Work on ASCII began in 1960. The first edition of the standard was published in 1963,[1] a major revision in 1967, and the most recent update in 1986. It currently defines codes for 128 characters: 33 are non-printing, mostly obsolete control characters that affect how text is processed, and 95 are printable characters.