class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of bits, usually four or eight. Special bit patterns are sometimes used for a sign or for other indications
Binary coded decimal is a way to encode numbers. The number is first split into digits, and each digit is then encoded in binary. This will result in a code from 0 0 0 0 (for "0") to "1 0 0 1" (for 9). The other codes (1010 to 1 1 1 1, representing the numbers 10 to 15) are not valid.
