Parity Bits
The use of a parity bit is the simplest form of error detection and consists of calculating whether the number of bits in a frame is even or odd
If it is even a 0 parity bit is appended to the end of the frame and if it is odd a 1 is appended
If a single parity bit were added to a package and it is subsequently garbled by a noise pulse, the probability of detecting the error is only 0.5, which is not good enough (i.e. 50 - 50 chance of changing its parity)