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Chapter 5— Linear Bar Codes
Code 93 or Code 9 of 3 Bar Codes
Interleaved 2 of 5 Bar Codes
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You use the Code 93 bar code for applications that require heavy error
checking capabilities. To accomplish this, the Code 93 bar code contains
two separate error checking checksums that are automatically calculated
and placed into the bar code. This bar code is used for inventories, hospital
applications, or any other place where the length may change between
items being scanned. This bar code type can use the entire ASCII 128
character set. It is useful for encoding data and phrases like "Code 93."
The two checksums in this bar code are located as the last and second to
the last characters in the decoded bar code. Code 93 has a complex
checksum calculation. Please see the bar code symbology specification for
information on how to create and decode this checksum. Please also note
that the bar code symbology specification does not state any ideal values
for the ratio and the width of the narrow bar.
You use the Interleaved 2 of 5 (or ITF) bar code for applications that have
a fixed data length for all items scanned. A date, telephone number, or a
SKU of fixed length is a good application for this bar code. The symbology
specification states that an ITF bar code may be partially decoded without
any recognizable difference. Therefore, to prevent this problem, you must
keep the length of data to a constant and perform an error checking
routine on the decoding program to determine if the data is correct.
Only the digits 0 through 9 can be encoded, and there should be an even
number of digits in the data. If there is an odd number of digits, the
printer automatically inserts a zero (0) at the beginning of the bar code.
There is no checksum automatically added to the bar code. You can,
however, manually calculate a checksum and append it as the last digit (or
least significant digit) in the bar code.
Step 1: To calculate the checksum, first ensure that you are starting with
an odd number of digits in the data. If not, add a zero (0) to the beginning
of the data.
Step 2: Multiply every other digit by 3, and add up the numbers including
the skipped bar code digits. So, if your data was 43827, your calculation
should be (4 x 3) + 3 + (8 x 3) + 2 + (7 x 3) = 62.
Step 3: Divide this number by 10, resulting in 6 with a remainder of 2.
Subtract the remainder from 10. In our example, 10 - 2 = 8. The
checksum is this final number, 8. Append this to the end of your data.
Note that if the remainder was a zero, your checksum should be zero.
EasyCoder PL-Series Printer Programmer's Reference Manual
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