Introduction
Codabar was developed in 1972 by Pitney Bowse, Inc. Codabar is a
discreate, self-checking symbology. In Japan, it is called
NW-7(Japanese
standard JIS X0503)
Codabar has a character set of 16 letters:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
-, $, :, /, ., +
Codabar has four start/stop characters we refer here as A, B, C and D.
Codabar is used in US blood banks, photo labs, and Fedex airbills.
The minimum value of X is 7.5 mils. The wide-to-narrow (N) ratio shall
be between 2.0 and 3.0 and remains constant in the symbol, and N must
exceed 2.2 if X is less than 20 mils. The minimum bar height is 15 percent
of the symbol length or 0.25 inches, whichever is greater.
Variants
There is no check digit required for codabar, though some applications
opt to append a check digit at the end of the message.
FedEx Airbills use a variant of codabar. A FedEx airbill number has the
format of XXXX-XXXX-XXXY with an additional 4-digit format ID. The Y
character is a check digit with the algorithm unknown to public. The first
12 digits is the track number. The barcode itself starts with start/stop
character C and ends with start/stop character D.
Structure of a codabar barcode
A typical codabar barcode has the following structure:
- A start character from 4 choices: A, B, C and D.
- Inter-character gap space
- Encoded message
- A stop character from 4 choices: A, B, C and D.
Check Digit Calculation
No check digit is used in Codabar symbology.
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