MAINTENANCE AND ACCESSORIES
SECTION 8.5
8.5.4
VER.V09F
CODE 39
CODE 39 is an alphanumeric bar code consisting of 43 data
characters (0-9, A-Z, 6 symbols and space) and a unique
start/ stop character
"*"· These characters are represented by
light and dark bands, as shown in Fig 8.5, CHARACTER BAR CODE.
Code·39 is so named due to the structure of each character being
represented by 9 elements (5 bars and 4 spaces) 3 of which are
wide and the remaining 6 are narrow. A wide bar or space is
assigned a value 1, and a narrow bar or space is assigned a
value O. Gaps between characters have no value.
The number of characters in a code is limited only by the
capabilities of the reader equipment or by human factors if a
hand held wand is used.
Each code starts and ends with an asterisk,"*", thus the code
may be scanned in either direction.
The width of a unit bar may vary considerably allowing various
printing methods to be used to produce the characters, e.g:
offset, letter press, dot matrix printers. The recommended
standard density is 9.4 characters per inch, but a density of
1.4 characters per inch may be used for corrugated containers.
A complete Code 39 bar code consists of a leading white space
(referred to as a quiet zone), a start character, data
characters, a stop character and a trailing quiet zone.
A check digit may be produced if required and is modulus 43.
The check digit is the last data character and calculated in the
following manner:
Suppose the data characters are:
1234 5ABCDE/
then the sum of the data characters are:
1+2+3+4+5+10+11+12+13+14+40=115
Now, 115/43=2 Remainder 29
The check digit is the character corresponding to the value of
the remainder, which in this example is 29, i.e. "T".
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