No Parity

Parity checking is also used in communication between modems. Here, parity checking can be selected to be even (a successful transmission will form an even number) or odd. Users may also select no parity, meaning that the modems will not transmit or check a parity bit. When no parity is selected (or defaulted), it's assumed that there are other forms of checking that will detect any errors in transmission. No parity also usually means that the parity bit can be used for data, speeding up transmission. In modem-to-modem communication, the type of parity is coordinated by the sending and receiving modems before the transmission takes place. Specifically, the Peripheral Component Interconnect bus and the I/O bus controller use the odd parity method of error checking.

Parity Limitations