Page 319 - Sensors and Control Systems in Manufacturing

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Cha p te r

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Module boundaries

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FIGURE 6.1 Encoding of the binary string 10011100 by delta code (top) and
width code (bottom).

FIGURE 6.2 Specifi cations of the UPC symbol. The readable characters are
normally printed in OCR-B font.

A bar-code reader can handle several different bar-code stan-
dards, decoding the stripes without knowing in advance the particu-
lar standard. The military standard, code 1189, specifies the type of
coding to be used by the Department of Defense, which is a modifica-
tion of code 39. Code 39 consists of 44 characters, including the letters
A through Z. Because of its alphanumeric capabilities, code 39 is very
effective for manufacturing applications. Code 39 is structured as