Parity checking is the process that ensures accurate data transfer between nodes during communication.
How Parity Checking Works?
The sender and the receiver agrees in advance whether the data units will have even or odd number of 1s.
Even Parity
Even Parity means;
- If number of 1’s is even, parity bit value is 0.
- If number of 1s is odd, parity bit value is 1.
Odd Parity means;
- If number of 1’s is odd, parity bit value is 0.
- If number of 1’s is even, parity bit value is 1.
Advantages and Disadvantages of Parity Check
The advantage
- Errors on a noisy line can be caught quickly and only the errant word has to be re-transmitted.
The disadvantages
- Cannot detect all errors, So have to use a higher-level error detection mechanism, like CRC.
Error Correction during data Transmission
Sometimes data bits may get flipped due to various reasons. In such situations the data bit received is in error.
- Error detection is the process of identifying that the data bit has been altered during transmission.
- Error correction and recovery mechanisms are used to correct the data bits received in error and to recover the actual data bits.