Code 128 is a linear bar code symbology capable of encoding the full 128-character ASCII character set and extended character sets. This Symbology includes a checksum digit for verification, and the barcode may also be verified character-by-character verifying the parity of each data byte. It has been widely implemented in many applications where a relatively large amount of data must be encoded in a relatively small amount of space. Code 128 Code Sets Code Set A (or Chars Set A) includes all of the standard upper case U.S. alphanumeric keyboard characters and punctuation characters together with the control characters, (i.e. characters with ASCII values from 0 to 95 inclusive), and seven special characters. Code Set B (or Chars Set B) includes all of the standard upper case alphanumeric keyboard characters and punctuation characters together with the lower case alphabetic characters (i.e. characters with ASCII values from 32 to 127 inclusive), and seven special characters. Code Set C (or Chars Set C) includes the set of 100 digit pairs from 00 to 99 inclusive, as well as three special characters. This allows numeric data to be encoded as two data digits per symbol character, at effectively twice the density of standard data. Code 128 Special characters The last seven characters of Code Sets A and B (character values 96 - 102) and the last three characters of Code Set C (character values 100 - 102) are special non-data characters with no ASCII character equivalents, which have particular significance to the bar code reading device.
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