Method for detecting bit errors on digital signals. In simplest form, one parity bit is added to each byte (8 bits) of user data. For odd parity, the extra bit is set to a “1” or a “0” so as to make the binary sum of all nine bits equal to “1.” For even parity, the sum is made equal to “0.” If any one of the nine bits is changed, the sum will no longer be odd or even, and the byte will be marked as corrupted.