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Appendix A:
Bar Code Specifications
Code 39 Specifications
Code 39 (or Code 3 of 9) is the de facto standard of non-retail American industry. It is widely used in the automotive industry
(AIAG specifications) as well as in government and military applications (LOGMARS specifications). Code 39 is flexible, fea-
tures a large character set, variable data length and density, and bi-directional readability. Code 39 is extremely accurate; substitu-
tion errors are almost nonexistent. Its character set consists of numbers
0
through
9
, upper case
A-Z
, and characters
Space
,
$
,
%
.
/
+
and
-
.
The name "Code 39" comes from both the fact that its character set originally contained 39 characters (it now
has 43) and from its structure. Each character is formed of three wide and six narrow elements, made up of
five bars and four spaces. Code 39's density can vary from a low of .75 characters per inch (cpi) to a high of
9.4 cpi. There should be a ¼" "
quiet zone
" (white space) to the left and right of the bar code.
Code 39 uses an asterisk (
*
) as a start and stop character. This character must precede and follow the data in
the bar code. The RF Terminal gives you the option of transmitting or not transmitting these characters when the bar code is read.
Exact specifications for Code 39 and other bar code symbologies can be obtained from ANSI at the address below:
American National Standards Institute
Customer Service
11 West 42
nd
St.
New York, NY 10036
http://web.ansi.org
document ANSI/AIM BC1-1995
Code 39 has several advanced features and functions that are discussed further in this appendix.
Code 39 Advanced Features and Functions
Mod 43 Check Character
Standard Code 39 can be printed with a "
Mod 43 Check Character
". This Mod 43 check character
cannot
be used with
Full
ASCII Code 39
. Assigning a value to each character in the data to be bar coded from the table as follows derives the check char-
acter:
Char
value
Char
value
Char
value
Char
value
0
0
B
11
M
22
X
33
1
1
C
12
N
23
Y
34
2
2
D
13
O
24
Z
35
3
3
E
14
P
25
-
36
4
4
F
15
Q
26
.
37
5
5
G
16
R
27
space
38
6
6
H
17
S
28
$
39
7
7
I
18
T
29
/
40
8
8
J
19
U
30
+
41
9
9
K
20
V
31
%
42
A
10
L
21
W
32
Mod 43 Check character calculation for Code 39
Here is an example to illustrate how the check character is calculated for bar code data of
123XYZ
:
Take the sum of the values assigned to each character:
1 + 2 + 3 + 33 + 34 + 35 = 108
1 2 3 X Y Z
*C39*
Содержание 7100 RF Terminal Series
Страница 5: ......
