extended binary coded decimal interchange code (EBCDIC)
The Extended Binary Coded Decimal Interchange Code (EBCDIC) is an extended 8-bit code developed by IBM and used in IBM mainframes as internal processing code. It can be used without code conversion, e.g. with the standardized ASCII character set for data transmission. The EBCDIC code consists of letters, digits, control characters and graphic symbols.
In EBCDIC, the bytes are divided into a zone part and a digit part, with each byte divided into two quadbits or nibbles. One quadbit represents the zone part, the second one the digit part. The displayable characters are divided into groups, the group coding is done in the zone part. Within a group, the characters are numbered consecutively and are specified in the digit part. Since EBCDIC does not assign letters, digits or characters to all 256 possible combinations, the unassigned combinations can be used for user-specific implementations.
There are several variants of EBCDIC which are incompatible with each other. The American variant uses largely the same characters as the ASCII code. However, some characters are not contained in the respective other code.
A conversion from the EBCDIC code to ASCII is only possible via code tables.