What is an additional bit transmitted with a byte to detect errors called?

The additional bit transmitted with a byte to detect errors is known as a parity bit. This bit is added to a string of bits to ensure that the total number of set bits (ones) is even or odd, depending on the system being used (even parity or odd parity). When data is transmitted, the receiving end can count the number of ones and determine if it matches the expected parity. If there is a discrepancy, it suggests that an error has occurred during transmission.

This method provides a simple mechanism for error checking, though it is limited in its capabilities. It can detect single-bit errors, but it fails to catch situations where two bits are flipped, neutralizing each other's effects. Despite this limitation, the parity bit is a widely used and efficient method for basic error detection in digital communications.