Cyclical redundancy check (CRC)

A process used to check the integrity of a block of data. It provides an integrity check of the data before it is sent out into the wide area network. Its value depends on the hexadecimal value of the number of 1s in the data block. The transmitting device calculates the value and appends it to the data block; the receiving end makes a similar calculation and compares its results to the added character. If there is a difference, the recipient requests retransmission.