Bar code technology has been in wide use since the late seventies and today bar code labels can be seen on most products as an internationally recognised method of quick, simple and accurate character identification.
Bar code is a printed sequence of parallel bars and spaces that are arranged in a predetermined order to represent characters.
A linear bar code contains a start character, several data characters (including in most cases a check digit), and a stop character. Each character is made up of a unique combination of bars, bar widths and spaces for which strict rules apply making it practically impossible for the bar code label to be read incorrectly.
Bar codes can be read by a variety of devices from hand held wands to industrial conveyor belt systems but the principle is much the same. By passing a small beam of light across the whole length of the printed code, the signals received from the scanner are processed by a Decoding unit that performs an algorithm to interpret the signals into meaningful data.
Most scanning systems are bi-directional and have the ability to read the code successfully whether the scanning motion is from left to right or right to left.
As more information is required on a bar code the label will become longer and higher to accommodate the reading devices that are used to scan the information.
The latest type of bar codes are 2D (two dimensional) in which data is encoded in both the horizontal and vertical dimensions thereby increasing the amount of data in a small space.