How UPC Bar Codes Work ?
Most people have become so used to the bar codes used on products that they don’t think about them anymore. These strips of black and white are known by the more formal name – Universal Product Code (UPC). There are several types of bar code and the UPC style used on most retail products is just one of those. A set of bars makes up the largest part of these identifying codes. But there are also numbers under the strips that correspond to the bars.
In a UPC code, numbers that make up prices are shown by different bars and spaces between these bars. A number is shown in a set of seven bar units. If the scanner cannot determine the product code from the bars the printed numbers provide a backup system for identification.
To read the bar code, you need a scanning light that interprets the white spaces and black bars that are of different widths. This information is converted to digital format so that the computer can work with it. (Think of a cash register as a special type of computer that receives the information provided by bar codes.) The bar code tells the receiving computer/cash register what the product is, essentially allowing the system to obtain a description of the product. At this point, a price is connected with the product description. The price is generally not part of the bar code.
One of the most interesting facts about UPC bar codes is that a pattern of thin lines in the center is often used to distinguish numbers on one side of center from numbers on the other side of center. In fact, data indicated by a bar on one side of this center mark is indicated by a space on the other side.
UPC bar codes may have 8 digits or characters in some situations, while a product code may have 12 digits or characters in other applications. The shorter version helps speed the process up and make it more efficient by suppressing the zeros. Example: 055001 005321 could be made shorter by eliminating some zeros.
In most standard UPC bar code systems the first six digits indicate the manufacturer, as listed in a Uniform Code Council database. Codes beginning with certain numbers might indicate produce while another might indicate items from the health/beauty category. In general use, five digits are used to identify a particular item within the general category.
Bar codes have been used for years to identify objects and products in industry and commercial locations. But these codes are most commonly used in retail stores – clothing, grocery, electronics and so on. In the massive inventory of products available for purchase, bar codes help simplify the buying process and make it accurate for revenue and inventory purposes.
Bar codes differ from radio-frequency identification (RFID) in that the bar code is “read” optically while RFID relies on signals transmitted from a sending location to a receiving location. Bar codes are still less costly than other methods that have been tried.
Category: Technology