The document discusses different character sets used in computing. It describes the ASCII character set which uses 128 characters and numbers to represent English letters, numbers and symbols. It also discusses the extended character set which includes 255 characters like symbols and international letters. Finally, it introduces Unicode which began in 1989 and aims to support encoding for all languages and alphabets in the world using up to 65,000 characters, grouping related symbols into scripts to serve multiple languages.