How does longitudinal parity work??

What will be an ideal response?

?The first step of this parity scheme involves grouping individual characters together in a block. Each character (also called a row) in the block has its own parity bit. In addition, after a certain number of characters are sent, a row of parity bits, or a block character check, is also sent. Each parity bit in this last row is a parity check for all the bits in the column above it. If one bit is altered in Row 1, the parity bit at the end of Row 1 signals an error. In addition, the parity bit for the corresponding column also signals an error. If two bits in Row 1 are flipped, the Row 1 parity check will not signal an error, but two column parity checks will signal errors. This is how longitudinal parity is able to detect more errors than simple parity. Note, however, that if two bits are flipped in Row 1 and two bits are flipped in Row 2, and the errors occur in the same column, no errors will be detected.