Introduction
Code 93 was designed to provide a higher density and data security
enhancement to Code39. It is an alphanumeric, variable length
symbology. code93 is used primarily by Canadian postal office to encode
supplementary delivery information. Every symbol includes two check
characters.
Code93 is designed to encode 26 upper case letters, 10 digits
and 7
special characters:
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V,
W, X, Y, Z
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
-, .,
$, /, +, %, SPACE.
Each Code93 character is divided into nine modules and always has three
bars and three spaces. In this way comes the symbology name.
In addition to 43 characters, code93 defines 5 special characters:
  
and .
represents
start/stop characters; while the last four circular symbols can be
combined with other characters to unambiguously represent all 128 ASCII
characters. The character encoding under the full ASCII mode is very
similar to the one in extended Code39 except the
component characters, $, %, / and + are replaced by 4 special characters  
and
respectively.
In an open system, the minimum value of X dimension is 7.5 mils. the
minimum bar height is 15 percent of the symbol length or 0.25
inches, whichever is greater. The starting and trailing quiet
zone should be at least 0.25 inches.
Structure of a code 93 barcode
A typical code 93 barcode has the following structure:
- A start character –
 - Message encoded
- First check character "C"
- Second check character "K"
- Stop Character -

- Termination bar
|
CODE93 CHAR TABLE |
|
Ch |
Val |
Ch |
Val |
Ch |
val |
ch |
Val |
|
0 |
0 |
A |
10 |
N |
23 |
- |
36 |
|
1 |
1 |
B |
11 |
O |
24 |
. |
37 |
|
2 |
2 |
C |
12 |
P |
25 |
sp |
38 |
|
3 |
3 |
D |
13 |
Q |
26 |
$ |
39 |
|
4 |
4 |
E |
14 |
R |
27 |
/ |
40 |
|
5 |
5 |
F |
14 |
S |
28 |
+ |
41 |
|
6 |
6 |
G |
16 |
T |
29 |
% |
42 |
|
7 |
7 |
H |
17 |
U |
30 |
 |
43 |
|
8 |
8 |
I |
18 |
V |
31 |
 |
44 |
|
9 |
9 |
J |
19 |
W |
32 |
 |
45 |
|
|
K |
20 |
X |
33 |
 |
46 |
|
|
L |
21 |
Y |
34 |
|
|
|
|
M |
22 |
Z |
35 |
|
|
Check Digit Calculation
To calculate the check character "C" and "K", follow the following steps.
- Take the value (0 through 47)
of each character in the barcode (see the table to the
left). The start and stop
characters are not included in the checksum
calculation.
- Assign the weight for each character. The right-most character has a
weight value of 1, the second to last 2 and so on. After 20,
the sequence goes back to 1.
- Multiply the character value with weight. Sum all the results.
- Divide the result by 47 and get the
remainder. Reverse look up the remainder to get the character. This
is check character "C".
- Append the "C" character at the end of
the data, and repeat the step1 through step 4. This time the weight
ranges from 1 to 15. The result is the character "K".
Web Tool
At barcode knowledge library we provide free web-based utilities for
readers to calculate check digits, performing number conversions. To
calculate code93 check digit, refer to this page. If you have
purchased Morovia Code39 Font, you may consider checking out
this
page for additional utilities for character mapping.
|