scope:

In data communication systems the information formats and the redundancy in the data to be transmitted differ widely from one application to another. It is therefore clear that a number of classes of error protection systems may be required. This International Standard defines one method of error detection which satisfies a wide range of applications. It consists of accompanying the data block or text by one checking character (in addition to char acter parity) and it is often referred to as the "Longitudinal Parity Method".