Longitudinal redundancy check
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In telecommunication, a longitudinal redundancy check (LRC) or horizontal redundancy check is a form of redundancy check based on the formation of a block check following preset rules.
- The block check formation rules are applied in the same manner to each character.
- A combination of longitudinal and vertical redundancy check allows the detection and correction of single bit errors.
Source: from Federal Standard 1037C and from MIL-STD-188
A longitudinal redundancy check character, which is used to verify that
data has been received without error, may be computed from any sequence of
characters by the following algorithm:
Set LRC = 0
While there is another character in the string
do
Set c equal to the next character
Set LRC equal to LRC XOR c
end do
“LRC XOR c” specifies that corresponding bits of LRC and c should be exclusive-or’ed and the resultant bit values should become the values of the corresponding bit of the result.