Wikipedia
A parity bit, or check bit, is a bit added to a string of binary code Parity bits are used as the simplest form of error detecting code Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes), although they can also be applied separately to an entire message string of bits The parity bit ensures that the total number of 1-bits in the string is even or odd Accordingly, there are two variants of parity bits: even parity bit and odd parity bit In the case of even parity, for a given set of bits, the occurrences of bits whose value is 1 are counted
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