The Universal Product Code has been used in the North American retail industry since 1973. There are two different versions of UPC bar codes, UPC-A and UPC-E. The UPC-A bar code is 12 digits long, including its checksum. UPC-E bar codes are special shortened versions of UPC-A bar codes and are 6 digits long. Both UPC-A and UPC-E bar codes may have optional 2 or 5 digit supplemental codes appended
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