Parity bit

A bit added to a data unit so its total number of 1s is even or odd. It detects some transmission or storage errors but cannot correct them.

Even parity: A parity convention in which the total number of 1s, including the parity bit, is even. The parity bit is set to make this count even.
Parity memory: Computer memory that stores an extra parity bit with each data unit to detect certain errors. It applies parity checks to data held in memory.
Checksum: A compact value calculated from data to help detect accidental changes. Checksums summarize larger data units, while parity tracks bit-count parity.
Bit: A binary digit that represents one of two values, usually 0 or 1. A parity bit is itself a bit appended to other bits.
Odd parity: A parity convention in which the total number of 1s, including the parity bit, is odd. This alternative sets the bit to make the count odd.
Serial communication: The transmission of data one bit at a time over a communication channel. Serial protocols may append a parity bit to each character.
Cyclic redundancy check: An error-detection code that treats bit strings as polynomials and computes a remainder. CRCs detect many error patterns that a single parity bit misses.
Binary numeral system: A positional numeral system using the digits 0 and 1. Parity counts the 1s in a binary data unit.
Hamming distance: The number of positions at which two equal-length strings differ. Parity detects any odd number of bit flips because those flips change parity.
UART: A hardware interface that sends and receives asynchronous serial data. UART frames commonly support optional parity bits.

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