back to the transmitter for the information to be re-transmitted.Forward Error Control such as the Hamming Code detects the presence and location of an error and thus the receiver can correct the data (by inverting the bit). Sufficient redundant bits are added to each block of data to identify and therefore correct errors on receipt.The use of parity can be extended to two dimensions, in which case it may be possible to locate and correct error. Consider the 7 by 7 data block with row and column parity bits added.01010000bold = data10001011normal = parity bits101110111000110100101011100010001010000011101110A single error is detected and located and can be corrected.Using even parity, there should be an even number of “1” in each row and column....
