Intermec EasyCoder PL-Series, Programmer'S Reference Manual

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Chapter 5— Linear Bar Codes
EasyCoder PL-Series Printer Programmer’s Reference Manual 41
Interleaved 2 of 5 Specifications
Bar Code
Symbology
Bar Code
Type
Input
Length
Characters Ideal
Wide/Narrow
Ratio Ideal
Narrow Dot
Width
Checksum
Calculation
Interleaved 2 of 5 I2OF5 Varies 0-9 only 2.5:1 2 See text
Code 128 and the UCC-128 Shipping Standard
You use Code 128 for applications that need to contain a large amount of
data such as shipping applications, marking blood donations, and any
other application that can vary in length between bar codes being scanned.
The bar code also contains a checksum as the last character in the code
that ensures that data remains intact.
Code 128 can use the entire ASCII 128 character set as well as other
subsets available in the universal symbology specification. The three start
and stop characters determine which character set to use. The checksum
for this bar code is located immediately before the stop character. The bar
code symbology specification contains all the information on calculating
this checksum. For a short example, we desire to encode BAR128 in a bar
code. In this example, you use A as your start and stop character.
Step 1: The symbology specification assigns a numerical value for each
character. Find the values of all the characters in the data.
Step 2: Add the value of the start character and all the data characters
multiplied by its position in the bar code. For our example, the calculation
would be 103 + (34 x 1) + (32 x 2) + (50 x 3) + (17 x 4) + (18 x 5) + (24 x
6) = 672.
Step 3: Divide this number by 103. The remainder or modulo, 54, is the
checksum. The character that is assigned to 54 in the specification is V.
Our final code looks like ABAR128V where A is the start character;
BAR128 is the data, and V is the checksum.
The UCC-128 Shipping Standard is part of a document called Application
Standard for Shipping Container Codes available from the Uniform Code
Council. This 90-page guide contains the entire specification on marking
any shipment sent anywhere in the U.S.A. Seventeen pages are dedicated
to the technical considerations of using, placing, and printing these bar
codes. We highly recommend getting this information if your application
involves shipping.