Parity, Checksum, and Cyclic Redundancy Check (CRC)

Parity is actually an extra bit that’s added to every data word. It can detect a one bit error within that data or byte 

Checksum is a sum all of the characters in the message. The sum is sent to the receiver along with the message.

CRC is a cyclic redundancy check. It is a fairly complex calculation that can be done on the data. Looking at each byte of data you then send this calculated CRC to the receiver.

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Watch I/O in a Minute: Parity, Checksum, and CRC