The Parity is a simple method used for error detection in serial communication, such as RS-232C. It involves adding an extra bit, called a parity bit, to each character or byte being transmitted. The purpose of this bit is to make the total number of '1's in the data either even or odd, depending on the type of parity being used. There are two main types:
Even Parity: The value of the parity bit is set to 0 or 1 to ensure that the total number of 1s in the byte (including the parity bit) is an even number.
Odd Parity: The value of the parity bit is set to ensure that the total number of 1s is an odd number.
The sending device calculates and appends the parity bit to the data. The receiving device performs the same calculation on the data it receives and compares its result with the received parity bit. If they do not match, the receiver knows that a bit error (a bit that flipped from 0 to 1 or vice versa) has occurred during transmission. For communication to work, both the sender and receiver must be configured to use the same type of parity (Even, Odd, or None). While parity checking is simple to implement, it has a major limitation: it can only reliably detect an odd number of bit errors (1, 3, 5, etc.). If an even number of bits are flipped, the parity will still appear correct, and the error will go undetected. For this reason, more robust error-checking methods like checksums and Cyclic Redundancy Checks (CRC) are used in more modern and critical communication protocols.