Transmission exceptions may happen due to different causes for example power surges or interference may delete data during transmission. In result of which the bits are deleted or the bit value may be modified.
ERROR CORRECTION AND DETECTION:
To correct and detect errors, frames add additional information, which is
checked by the receiver and inserted by the sender. In this way incorrect data may be
rejected. Also the incorrect data may be accepted and corrected.
To find the error there are different functions in which parity checking is also usually used. In parity checking, parity denotes to the number of bits set to 1 in the data item.
There are two kinds:
In an even parity the no. of 1's in packet would be an even number.
In an Odd parity the no. of in packet bits would be an odd number.