Written by: Pam Burnham
9/3/2008 

Barcodes are not as mysterious as you may think. You may want to compare a bar code to shorthand, Morse code or Braille Each of these have some type of symbols that represent letters and numbers. In the end, the interpretation will be the same. A traditional 1D (1 

dimensional or linear) barcode is made up of a series of bars and spaces with varying widths. These patterns are grouped together to form a "symbology." A barcode scanner is used to decode, interpret or translate those bars, just like the person that has been taught to read braille, shorthand, or translate Morse code. (Click on the barcode to view a standard 1D barcode example.)

Hopefully this makes some sense.... but I know what you are probably thinking. Isn't there different types of barcodes? How do I know what type I should use? What symbology will work with the bar code scanner or the software I have or will be purchasing?

Yes. there are different symbologies for barcodes. On a very simple level, you might think of the different symbologies as different fonts or perhaps you might think of symbologies as different languages.

Of course bar code symbology is actually more complex. Many are set based on an industry standard and incorporate a set of rules. For example, a UPC code, which almost everyone is familiar with, is widely used in retail. UPC stands for Universal Product Code. You can't just start using a UPC bar code.  A manufacturer applies to the UCC for permission to enter the UPC system. The UCC issues the manufacturer a six-digit manufacturer identification number and provides guidelines on how to use it. The next five digits of a UPC barcode would represent the item number. An item number must be unique to each type of product as well as each package size of that product. The final digit is the check digit and is calculated based on the other 11. So as you can see with this example, there is a set of rules applied to this particular symbology. If you happen to be using the manufacturer's item number as your GP item number or perhaps would like to set it up as a cross reference number to your GP item number, don't worry, the actual manufacturer manages these numbers. For your purpose, it is just another reprentative number for the item.

There are entire books written on bar code symbology and technology in general. If you are really interested in learning more, just let me know and I can point you to some web sites or make a recommendation on a book. For most of you reading this, For most of you, you just want advise on what type of bar code to use to label your stuff.

First, you don't need to worry too much about what symbology is compatible with our software, with GP, or with the bar code scanning hardware you have or will be purchasing. It is up to the scanner to interpret the bar code and most bar code scanners will read any of the standard 1D symbologies (consider them multilingual). If you plan on using or need to read a 2D (2 dimensional) bar code (click on the picture to the right to view an example) ... then you will need to go with an imager which can read both 1D and 2D bar codes. I won't go into any further details on 2D barcodes with this blog, but please call me if you need or want to learn more.

If you are bar coding your inventory internally and don't have an industry standard to comply with, we typically recommend Code 128. It supports full alpha and numeric characters as well as all standard ASCII symbols and control codes. It has excellent density, has high reliability, and is widely used. In studies conducted by the University of Ohio, the Code 128 real life accuracy testing came in as one of the highest for 1D bar codes. The worst case  is 1 error in 2.8M characters. Best case, 1 error in 37M characters.  Just in case you are wondering, the best-trained entry operator will make a keystroke entry error once every 300 keystrokes.

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