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Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →A vertical redundancy check (VRC) is a simple error-detection method that adds one parity bit to each data unit or character. The sender and receiver agree to use either even or odd parity; the receiver checks that rule to detect certain transmission errors. VRC can signal a problem, but it cannot identify or repair the corrupted bit on its own.
What is VRC in computer networks?
Vertical redundancy check is another name for a parity check, also called character parity. Before sending a data unit, the sender adds one redundant bit—the parity bit. The receiver counts the 1 bits in the received unit and checks whether the total follows the agreed parity rule.
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Both ends must use the same convention. If one uses even parity and the other uses odd parity, a correctly transmitted unit can be treated as an error.
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Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →How does the parity bit work?
Even parity
The parity bit is chosen so the complete unit, including the parity bit, contains an even number of 1s.
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Odd parity
The parity bit is chosen so the complete unit contains an odd number of 1s.
Example using even parity
The seven-bit data 1100001 contains three 1s. With even parity, append a 1 as the parity bit, giving 11000011. The resulting eight-bit unit contains four 1s, an even total. This example shows the parity bit at the end; its position and the bit-order convention depend on the protocol or representation.
What errors can VRC detect?
If exactly one bit changes during transmission, the number of 1s changes between odd and even, so the parity check fails. The receiver can detect that the unit does not meet the agreed rule.
VRC can miss corruption when an even number of bits change: the total may still have the required parity. A parity match therefore does not prove that the data arrived unchanged.
Can VRC correct an error?
No. A parity mismatch tells the receiver that an error is present, but VRC alone does not locate the changed bit or determine its original value. It detects certain errors; it does not correct them.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What does VRC add to transmitted data?
VRC adds one check bit for each protected data unit or character. Its operation is straightforward, but its detection ability is limited by parity: any corruption that changes an even number of bits may preserve the check. Longitudinal redundancy checking (LRC) and cyclic redundancy checking (CRC) are also error-checking methods, but their comparative performance depends on the specific method and error patterns; a universal ranking is not established here.
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