In asynchronous communications and primary storage, an extra bit in the form of a check bit appended to an array of information bits for error control purposes. The parity bit is added to ensure that the total value of the bits, including the parity bit, is always either odd or even, depending on whether the communicating stations are set for odd parity or even parity. One or more parity bits are generally associated with a character, word, or block for purposes of checking the integrity of data after transmission or after storage and retrieval.When using ACSII code, for example, an eighth bit is always appended to each character as a parity check bit. In ASCII, the upper case letter A is represented by the binary code 1000001, which comprises an even number (2) of 1 bits. If the machine is set for even parity, a 0 bit is appended in the eighth bit position to retain the even value. If the machine is set for odd parity, a 1 bit is appended in the eighth bit position to create an odd value.The default is odd parity. See also ASCII, asynchronous, binary, block, code, error control, parity, and parity check.