A barcode is a series of wide and narrow bars that can be scanned. There are many different types of barcodes you can put on your plastic cards; the most common one seen is the Universal Product Code or UPC code that you see on items that you purchase at stores. You can scan the barcode with your barcode scanner and it will then bring up the information that is stored in your system from the barcode. A number can also be printed that is associated with the barcode as a human readable number on your plastic cards. So if your barcode did not scan you can also manually type in the barcode number in which it would bring up the same information that is stored. The type of barcode you will need will be dependent on the type of system you have. This information would be found through your product provider. There are many different types of barcodes that are used today so all we would need to know is the type of barcode you will need and the number sequence that you would like to use on your plastic cards.