The Design
#1 UPC Bar Code, as I mentioned earlier, is divided in two
sections. Left side is the manufacturers code and the right side
is the product code. Set #1 is the line configurations used for
the manufacturers code and Set #2,is used for the product code.
As the laser from the scanner scans across the code mark, the
computer can tell the difference between the two sides by the
difference in the code sets. So it doesn't matter which
direction the code is scanned, and the proper order of the code
is maintained. Each numbered code in both sets, has two lines to
make up the code number, and each number has it's own distinct
two line configuration. This way, the computer by the (eye)
scanner sees each individual number. When we buy items at the
store (most supermarkets today) we take them to the check out
counter and the checker runs the items across the scanner window
where a beam of laser light flashes across the UPC bar code. As
this happens the computer converts the code into binary (1's and
0's) code and then processes the information in the CPU of the
computer. Then the price of the item is display at the checkout
counter (almost instantly) and when we pay for the items that we
have bought, we get a receipt with the products that we bought
listed and the price of each individual product.
What happens
is, the laser light is reflected off the bar code and inside the
scanner window is a receiver that picks up the reflections.
Where the code has a line the reflection is different then where
the code does not have a line, so the receiver reads it a little
differently.
