EBCDIC (Extended Binary Coded Decimal Interchange Code ) (pronounced either "ehb-suh-dik" or "ehb-kuh-dik") is a binary code for alphabetic and numeric characters that IBM developed for its larger operating systems. It is the code for text files that is used in IBM's OS/390 operating system for its S/390 servers and that thousands of corporations use for their legacy applications and databases. In an EBCDIC file, each alphabetic or numeric character is represented with an 8-bit binary number (a string of eight 0's or 1's). 256 possible characters (letters of the alphabet, numerals, and special characters) are defined.
IBM's PC and workstation operating systems do not use IBM's proprietary EBCDIC. Instead, they use the industry standard code for text, ASCII. Conversion programs allow different operating systems to change a file from one code to another.
Also see Unicode.