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Computer Science IGCSEPDF 14
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6. Error Detection Methods
Parity Checks
● Adds a parity bit (extra bit at left).
● Even parity: total number of 1s must be even.
● Odd parity: total number of 1s must be odd.
● Sender and receiver agree on parity before transmission.
● Change in parity → error detected.
Limitations:
● Cannot detect if 2 bits flip.
● Can detect an error but not identify its position.
Parity Blocks:
● Apply parity to both rows and columns.
● Helps identify the exact bit where the error occurred.
· Firstly, the table indicates that an error occurred during data
transmission, as there is a change in the parity of one of the bytes.