Used for everything from ringing up groceries, to keeping inventory, to tracking ticket usage, barcodes have helped to streamline many businesses.
Barcodes are an essential part of modern civilization. Used for everything from ringing up groceries, to keeping inventory, to tracking ticket usage, barcodes have streamlined many businesses and sped up many processes by presenting an optical machine readable representation of data.
There are many different types of barcodes ranging from linear barcodes to two dimensional (2D) barcodes or matrix codes. Matrix codes do not actually contain bars, but the principle is similar to that of linear barcodes, which contain data in the widths and spacing of parallel lines of the one dimensional image. The most common is the Universal Product Code, or UPC.
In the UPC barcode, each digit is coded by stripes. There are two black stripes and two white stripes. Each stripe has a width ranging from one to four units with the total width of each digit being seven units.
This type of barcode is made up of 12 digits divided into various groups. The first two digits designate the country that issued the barcode. The next four digits identify the manufacturer. If a country has a three-digit country code, it will only have a three-digit manufacturer code. The remaining six digits are assigned by the manufacturer and are unique to the product. Each product must have a separate code. This is true for different sizes of the same product also.
A manufacturer must apply to the Uniform Code Council (UCC) for permission to enter the UPC system. The UCC issues the manufacturer the six-digit manufacturer's code and provides them with proper guidelines for using that code. The manufacturer, in turn, must pay an annual fee for the right to use the assigned code.
How do Barcodes Work?
A barcode must be read by a scanner to decode its data. There are three main categories of barcode scanners.
RS-232 barcode scanner
This is an older type that requires special programming to transfer the input data to the application program.
PS/2 or AT keyboard
Connects to the computer with an adapter cable.
USB barcode scanner
The modern device usually used today. This type is easily installed and does not require special programming.
Whatever type of system a company has, the barcode is placed under the scanner, or the scanner is run over the barcode and the data is sent to the computer for deciphering. The last digit of the barcode is usually a check digit. The computer performs a calculation based on the barcode and the check digit helps the computer determine if the scanner has read the code properly. If not, the item will need to be rescanned.
Laser barcode scanners project a thin, laser beam. When a barcode is moved under the beam, a pattern of light is reflected back to the laser. It is read by an infrared sensor and decoded.
Some new barcode readers use small video cameras and video scanning technology to make the scanning process even speedier and more reliable, but this is not yet common.