Barcode Data Structure
It used to be that barcode quality was all about print quality. Even today, print quality is the only issue addressed by the ISO specifications for 1D and 2D barcodes. But as barcodes have been adopted into more industries and usages, the way the data is encoded has become another important barcode quality consideration.
Data encoding in barcodes must be done in a way which overcomes several challenges. The most obvious is to, well, encode the data. Related to this is the challenge of minimizing the possibility of mistakenly decoding incorrectly. This is relatively simple with barcodes that only encode numbers. It gets more complicated with alphanumeric barcodes and much more complicated when upper case and lower case alphabetical characters are included. Add to that a host of special characters such as ~!@#$%^&*()-+= and—you get the idea.
Now consider the likelihood that the 1D barcode could be scanned upside down or right side up. The data must be encoded in a way that self-corrects for data sequence. And there are yet other challenges we won’t go into here.
As barcodes expanded into more and more industries and usages, and barcode data capacity increased, it became necessary to uniquely identify, for example, a Code 128 barcode in a health care supply chain from a Code 128 barcode in a military supply chain. To crack this challenge, industry application specifications were developed to standardize the way in which certain industries structured the data in their barcodes. This is referred to as barcode syntax, and here are a few examples.
- HIBCC (Health Industry Barcode Communications Council) barcodes are prefixed with a + (plus) character, followed by this sequence of characters:
- GS1 Healthcare barcodes are prefixed with the Application Identifier (01) indicating a Global Trade Identification Number. This format is for very small healthcare items. Larger items will carry additional AI’s
- MIL STD 130N specifies how data is to be formatted on items for Defense Department suppliers. There are three primary formats, but the general structure is as follows:
These are examples only. There are numerous variations in how data is formatted depending upon many factors. Refer to the appropriate industry standard to determine the applicable barcode syntax.
Barcode syntax adds a lot of complexity to how the barcode is structured, but solves the problem of keeping otherwise very similar barcodes from mistakenly infiltrating the wrong supply chain.
Syntax is the key ingredient in establishing and expressing this uniqueness. It is not done via barcode symbology. A Code 128 barcode does not intrinsically distinguish its data from the same data in a Data Matrix code. When printing a barcode structured to an industry standard, not all format instruction characters are represented in human readable form.
Structuring barcodes correctly is a three step process:
- Use the latest version of label design software when creating the barcode file, and make sure it has up-to-date industry applications
- Refer to the latest version of the Industry Application standard when entering the barcode data into a label design software
- Test your barcodes with an ISO compliant barcode verifier which also tests for Industry Standard formatting. It should be recently calibrated and using the latest version software.