What is a bar code?


You’ve seen them.  They make your life easier, faster.  Those little black and white miracles that make checking out at the store fast and simple.  Bar Codes.  But have you ever really thought about what makes a bar code tick (or should I say scan)?

Simply put, a linear bar code (like the ones in the store)  is a pattern of alternating parallel bars and SPACES (yes, the spaces make up the code as well).  The bars and spaces of a linear bar code represent numbers and other characters that are machine readable when encoded within the bar code.  A bar code can be encoded with product ID numbers, an order number, a postal code, or any other information that you may want  entered into a computer.  There are numerous bar code symbologies that each encode data differently.  They are like languages. Each bar code “language” is read by a scanner programmed to read that particular bar code symbology.  Like languages, some are simple and some are complex.  Some encode only numerical data while others can encode alphanumeric.

In the case of the UPC code that you commonly see in the store, the products ID number is encoded into the bar code.  This ID number is unique to that product and manufacturer.  When a scanner reads that particular pattern of bars and spaces, it will reference a database to know exactly what that product is and how much the item costs.  However, bar codes are used for many applications in addition to product identification.  They are used in shipping, tracking and work in process.  They are also used for order entry, sortation, records, and even linking to on-line information.

There is no doubt that the bar code is an amazing innovation that we see every day and take for granted.  So, the next time you see that pattern of bars and spaces or are zipping through the checkout line, think about the amazing “language” that its written in and the message that it conveys.