What is a CRC in synchronous serial communications?

The Cyclic Redundancy Check (CRC) is a check value used to detect transmission errors in a frame or block of data. The transmitter encodes the calculated CRC value and appends it to the data transmitted. The receiver decodes the calculated CRC value and compares it to the received data. Errors in the CRC indicate data was corrupted during transmission.

With Sealevel synchronous serial adapters, the CRC is used to detect errors in the received address, control and data fields. It is generated based on specific polynomials and a starting sequence of either zeros or ones.