1 Comment for How do they program the scanners to read the bar codes for the price/item on merchandise?

• 1. Ted Pack  |  May 21st, 2007 at 4:01 pm

  Bar codes are thick and thin. There are half a dozen different code schemes based on how far away the bar code will be and how fast it is moving. A laser and a mirror “read” the bar code by converting the light and dark into numbers.

  For instance, at the cannery, a pallet (200+ cases) of Campbells’s Tomato soup go onto a box car. At the supermarket distribution center, a bar code reader at the recieving dock reads the number that says “I’m a pallet of soup”. The warehouse workers break down the ballet. They send four cases of the soup, four cases of sliced peaches, twelve cases of toilet paper . . . to your supermarket. At your supermarket’s receiving dock someone will scan the case bar codes. The bar codes on the cases say “I’m a box of 24 cans of Campbell’s Tomato Soup”.

  You buy a can of soup. The check-out clerk scans the bar code on the can. It says “I’m a can of Campbell’s tomato soup”.

  In each case the bar code is a series of numbers. The UPC on the item a consumer buys in the USA has 10 digits. the first five identify ther manufacturer (Campbells, Del Monte, Kimberly-Clarke . . .) The second five identify the product. (Tomato Soup, Cream of Mushroom soup, Chicken noodle soup . . .)

  In each case, the numbers translate into what it is and how many there are, just the way the computers at the DMV can tell you that license plate 123-ABC in Maryland is a blue Ford 150 pickup owned by John Smith of Baltimore.

  Every Wednesday the people in the HQ of your local supermarket update the prices and download the updates to the scanners at the checkout-stands; this week they may have a special, so your can of soup is 49 cents, down from 79.

  In the heart of the checkout computer, the scanner says “I read the bar code. it is 01234-56789″. The computer looks in its files for that number, tells the printer “Campbell’s Tomato Soup, regular size”, and this week it is 49 cents”. The 49 cents goes into the total. The printer may print “You saved 30 cents by shoppig at . . .”.

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