Parity check

Parity check is used to detect 1-bit errors (binary digit), e.g. when reading barcodes. A distinction is made between even and odd parity, depending on whether the sum of the bits of the checked character contains an even or odd number of bits with the value 1. For example, the character to be checked (with N digits) is extended by the so-called parity bit, which is set in such a way that a corresponding parity of the new character (with N+1 digits) is created. This means that not only 1-bit errors but all even-numbered bit errors are recognized with precision.

Source: logipedia / Fraunhofer IML