How Do Bar Codes at the Grocery Stores Work?
Bar codes can be found on just about every item sold in a retail store. Generally known as universal product codes, or UPCs, the black and white bars that make up each code are read by cash register computers and linked to a product and price stored in the electronic database of the grocery store or other place of business. Bar codes make the entry and addition of each product's price to a total bill quicker and easier.
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History
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The development of modern-day bar codes began in 1948, when Norman Woodland and Bernard Silver worked on a way to help grocery stores track inventory, which had become long, expensive, and tedious. The pair's early inventions, which involved a bull's-eye-shape bar code and a desk-size machine with a 500-watt light bulb, never caught on in grocery stores. But a similar idea developed by David J. Collins was used for a short period of time in limited areas to identify railroad cars.
It wasn't until 1972 that the idea of the bar code was used in a grocery store, being tested with bull's-eye codes in Cincinnati Kroger stores. The UPC-style bar code, as we see it today, wasn't used until April 1973. It was chosen over the bull's-eye codes because the ink used to print the codes smeared less when printed in straight lines.
Bar-Code Digits
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Each digit of a typical grocery store UPC bar code is made up of four vertical lines, two black and two white. The width of each of these lines ranges from one to four units wide. The combination of widths of the four lines that make up a digit determine the number that is communicated to the computer. When these line combinations are placed side-by-side, a number comprised of multiple digits can be communicated to a checkout computer.
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Bar Code Make-Up
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Different digits in a bar code typically communicate different things to a computer. The first digit of most grocery store bar codes indicates the type of item. A "0" usually indicates that the item is a national brand, a "2" means the product is a store-packaged deli meat or cheese, a "3" means the product is health- or beauty-related, "4" means the product's price has been reduced, and a "5" is generally the first digit of a UPC on a manufacturer's coupon.
The second through sixth digits in the code indicate the manufacturing or distributing company's ID number, and the seventh through 11th digits are the product's distinguishing identification number. The 12th and final digit is known as the "check digit," and it is used in a mathematical equation to make sure the entire UPC is valid.
Reading Bar Codes
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A cash register computer reads bar codes using a high-powered laser beam that is rapidly moving back and forth in order to allow hundreds of passes at the code within less than a second. The white lines in a bar code reflect the light back at the laser and the black lines absorb the light, sending a clear signal to the computer. The hundreds of passes that a laser takes at a bar code help the computer to verify that the correct UPC code is being read and inputted.
Bar codes also generally have a few lines added in or a few numbers printed backward so that the computer knows what the number is whether the code is read backward, forward, right side up or upside down.
Modern Bar Code Use
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Today bar codes are used not only in grocery stores, but in retail stores all over the world. Not all codes follow the same pattern as grocery store UPCs, but each is made up of patterns that a computer uses to identify a product and add its price to a bill. Bar codes have also made life simpler for consumers, because an item's bar code is the same at every store where that item is sold. In this way, recent applications on smart phones and other devices allow for quick price comparisons by simply swiping or taking a picture of a bar code.
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References
- Photo Credit barcode_02 image by Perth from Fotolia.com
Comments
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Thanks we need barcode cash machine in our business.
