
Computer Science
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Figure 5.6 A typical piece of bar-coding which can be used to place computer
data in coded form on paper. Dot-matrix printers can reproduce bar-codes, and
light-pens can be used to read the codes
and it is also possible, using a controlling program, to print bar codes with an
ordinary dot-matrix printer. One very common use of bar codes is to identify
stock items, and their use for this purpose is common in shops.
The reading of bar codes was originally carried out by a form of light-pen
which was moved across the coded bars. By detecting the reflected light, the
presence and width of eac ...