The 74F401 Cycle Redundancy Check (CRC) Generator/ Checker provides an advanced tool for implementing the most widely used error detection scheme in serial digital data handling systems. A 3-bit control input selects one-ofeight generator polynomials. The list of polynomials includes CRC-16 and CRC-CCITT as well as their reciprocals (reverse polynomials). Automatic right justification is incorporated for polynomials of degree less than 16. Separate clear and preset inputs are provided for floppy disk and other applications. The Error output indicates whether or not a transmission error has occurred. Another control input inhibits feedback during check word transmission. The 74F401 is fully compatible with all TTL families.