| 摘要 |
An add-on bar code reading apparatus used in a bar code reader identifies a block of a main-part bar code by detecting start and end guard-bars, determines a right end of the main-part bar code based upon whether all the characters in the block carry even parity, detects the add-on bar code a predetermined interval after the right end, and reads the add-on bar code thus-detected. The apparatus also determines whether a plurality of sets of add-on characters are read which have differing numbers of characters, compares the plurality of sets of add-on characters character-by-character for equality in character code and in parity, and determines whether the number of characters is equal to that of the set having the smallest number of characters. When a match is determined the set of add-on characters having the largest number of characters for the add-on bar code is selected.
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