# binary code (BC)

Binary code is a code in which each code word consists of binary characters, i.e. the two characters of the binary system. This can be 0 or 1, but also Hi or Lo and is represented by a bit.

The designation binary code only says that a character is binary coded. It says nothing about which valence and digitness the binary code has in the place value system: Is it 4-, 5-, 6-, 7- or 8- digit and is it based on a certain structure? Such a structure is shown by the fact that a binary code has only a certain number of ones. Examples of this are the 1-out-of-10 code or the 2-out-of-5 code. Such structures facilitate error detection and error correction. Another structural element of binary codes is the step sequence.

There are single-step and multi-step binary codes. In single-step codes, the bit pattern changes by only one bit per step, for example from 0100 to 0101. In multi-step codes, the bit pattern can change by several bits per step, for example from 0100 to 0111.

Since decimal digits are often encoded in binary, the binary code can be the 4-digit BCD code or another binary code such as the Aiken code or Excess-3 code. For 4-digit binary codes, the four dual numbers determine the assignment of valence to the binary code words. The order of the valence of the binary values can be quite different: 8-4-2-1 is it with the BCD code, 2-4-2-1 with the Aiken code or 16-8-4-2-1 with 5-bit codes.

The binary code is also used as an assignment code, for example in the ASCII character set. In this character set, each letter, digit, character and control character is uniquely identified by a binary code. Examples: Decimal number 5 corresponds to 0101 in the BCD code, decimal number 18 corresponds to 0001 0010 in the BCD code.