Error Correction

　　Error correction is the method by which modems verify that the information sent to them has been undamaged during the transfer. Error-correcting modems break up information into small packets, called frames. The sending modem attaches a checksum to each of these frames. The receiving modem checks whether the checksum matches the information sent. If not, the entire frame is resent. Though error correction may slow down data transfer on noisy lines, it does provide greater reliability. MNP2-4, as well as V.42, are error correction protocols. These protocols determine how the modems verify data. As with data compression protocols, for an error correction protocol to be used, it must be supported by both modems in the connection.