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Bars and Stripes Forever
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# : |
20012 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
8 / 1992 |
2,545 Words |
| Author
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John Schenck
John Schenck is professor of industrial technologies at
Northern State University in Aberdeen, South Dakota. He
became interested in bar coding 10 years age while
researching a textbook on technical communications. |
The busy shopper standing in line at the supermarket checkout gives scant attention to what happens as the clerk passes each grocery item over that X-shaped opening in the counter. A red light briefly flashes under the opening, is reflected from the grocery item back through the X-shaped opening, and the price and name of the item are displayed on a small video screen above the cash register. In that split second after the item moves over the X-shaped opening and before the price and name appear, a lot has happened. And it all has to do with something called bar codes.
Bar codes are machine-readable patterns of alternating parallel bars and spaces representing numbers and other characters. They are designed to store information in a form easily read, interpreted, and printed by machine. The information is coded into the widths of the bars and spaces of the printed symbol. Different arrangements of bars and space are called symbologies. Regardless of their codes or symbologies, all bar codes have the same birth date.
On October 20, 1949, Norman Woodland of Ventnor, New Jersey, and Bernard Silver of Philadelphia applied for a U.S. patent titled "Classifying Apparatus and Method." Their application described "the art of article classification . . . through the medium of identifying patterns." But bar coding had to be further developed before it could be put to general use; all the necessary components and technologies associated with it had to be developed. The scientific advance that rejuvenated interest in, and use of, bar coding was electronics in the form of semiconductors, microprocessors, and lasers. These three devices in particular made possible smaller, cost-effective scanners, in-house printers, and better, smaller computers. They also led to the proliferation of bar codes.
Many bar codes now exist, but the two major divisions of bar coding are universal product codes and industrial bar codes. Universal product codes include the ubiquitious Universal Product Code (UPC) that has become the bar code standard for the grocery industry in the United States and Canada and the European Article Numbering Code (EAN), which is the European equivalent of the UPC. Industrial bar codes in common use are Code 11, Interleaved 2 of 5, 2 of 5, Codabar, and Code 39. Industrial bar codes keep track of manufacturing processes, hospital supplies, the mail, luggage, and library books. The many industrial bar codes available differ primarily in the arrangement and number of their bars and spaces.
The Universal Product
...
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