Correcting Errors Correcting Errors One of the biggest problems with modems and phone line communication is the presence of errors. A simple way to do this is a parity check . A parity check works by sticking an extra bit at the end of each signal. An odd parity means that the total number of bits that have a value of 1 in a signal, including the parity bit, must be an odd number. If the total number excluding the parity bit is even, the parity bit will be 0.
Odd parity works similarly.
The receiving modem will examing the signal. This is by no means the only way of checking and correcting errors, but is the simplest.