Bar coding is a method of labeling retail products and other items. A bar code consists of a pattern of lines and bars that a computer can translate into information about an item. Many retail establishments have computerized cash registers that can read bar codes. Different groups administer and manage bar code standards for different areas of business. Perhaps the most important group is GS1, which manages a bar-coding system used by more than 100 countries, primarily in retail trade.
A bar code includes a number of digits or other characters that contain the same information as the bars and lines. In the GS1 system, bar codes for trade items are based on unique identification numbers called Global Trade Item Numbers (GTIN’s). A GTIN can be created using any of four main numbering schemes. The most widely used scheme includes 13 digits. The other three schemes have 8, 12, and 14 digits, respectively. However, the GS1 system can convert any GTIN into a 14-digit code by adding zeroes before shorter codes. Other bar-coding systems use different schemes.
At a store’s checkout counter, an optical scanner reads bar codes by beaming a light across a product’s code and interpreting it as a series of numbers. This scanner may be built into the counter under a small window. Or it may be a handheld device that the clerk points at the bar code. The store’s computer uses the sequence of numbers to search a database for product information. It relays the price and a short product description to the cash register, which displays this information on a screen and records the sale on a paper sales slip. The sale is also recorded in the computer, which thereby helps keep track of the store’s stock of each item. If the scanner fails to read the code, the store clerk keys the bar code’s characters into the computer.
The Universal Product Code (UPC), the original standard in the United States and Canada, was adopted in 1973. It first appeared on supermarket products in 1974. The European Article Number (EAN) code, the original standard in Europe, was adopted in 1976. Similar codes are used in factories, warehouses, hospitals, and libraries, especially for inventory control. Bar codes with lines or patterns that run both vertically and horizontally can store a large amount of data in a small space. Such codes are used on the back of some driver’s licenses to store information about the driver. A type of bar code called a QR code—short for quick response code—became popular with mobile phone users in the 2000’s. A QR code is a grid pattern that can be “scanned” with a phone’s camera, typically causing the phone to display a certain web page.
See also Cash register ; Laser (Scanning) ; Scanner .
