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Bars and stripes at the checkout

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Barcodes were developed by Norman Woodland and Bernard Silver, graduates at the Philadelphia Drexel Institute of Technology, in response to a request by a chain store owner for an automated checkout method for reading product information.

The inspiration came from Morse code; the dots and dashes were simply extended downwards to make machine-readable representation of data.

Woodland and Silver patented their innovation, and the associated reader system, in 1952. The patent covered both circular and linear systems. Although the former shape could be scanned in any direction, ink smearing rendered it useless. Linear codes are printed in the direction of the stripes, and any smearing simply makes the bars longer without loss of readability.

Elongated guard lines allow the computer to orientate itself to read from any direction. Two-dimensional geometric patterns are also used. Although they have no bars they are called barcodes.

Barcodes took a while to catch on. Widespread use depended on the adoption of a standard encoding system, which came in 1973 with the introduction of the Universal Product Code. The following year a UPC scanner was installed in an Ohio supermarket.

The 10-pack of Wrigley’s Juicy Fruit Gum and receipt that represented the first transaction are now on display in the Smithsonian Institution in Washington DC.

Results were not promising for the first few years. The scheme required a critical mass of retailers to adopt expensive scanners while manufacturers simultaneously adopted barcode labels, and neither wanted to move first.

But retailers were eventually swayed by the speed and extreme accuracy of barcode scanners compared with key entry. Depending on the type of barcode, the error rate ranges from about one in 15,000 characters entered to one in 36 trillion.

In addition to their applications in sales and inventory control, barcodes allow the rapid and unambiguous identification of documents and people. They are used in movement tracking of rental cars, airline luggage, nuclear waste and mail.

Many tickets now have barcodes that need to be validated before the holder can enter a sports arena or theatre. Recently, two-dimensional bar codes have been sent to mobile telephones to enable electronic boarding passes, and researchers have placed tiny barcodes on individual bees to track the insects’ mating habits.

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From: Beyond pharmacy blog

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