Hand Held Products Quick Check Bar Code Verifiers 800 User Manual page 79

A check character is a character placed in a predetermined position in a symbol
and whose value is based on some mathematical relationship of the other
characters in the symbol. It is used by the scanner to validate that the correct
data has been decoded. If a numeric symbology contains a check character, it
is often called a check digit.
The following illustration shows many of these bar code parameters.
Bar code symbol parameters
Quick Check® 600/800 Series User's Guide 6 - 5