Here is some information that will give you a basic introduction to barcodes.

If you go look in your refrigerator or pantry right now, you will find that just about every package you see has a UPC bar code printed on it. In fact, nearly every item that you purchase from a grocery store, department store and mass merchandiser has a UPC bar code on it somewhere.

What's a UPC Bar Code?
" UPC" stands for Universal Product Code. UPC bar codes were originally created to help grocery stores speed up the checkout process and keep better track of inventory, but the system quickly spread to all other retail products because it was so successful.

How does a barcode work?
Each character is represented by a pattern of wide and narrow bars. A barcode reader uses a photosensor to convert the barcode into an electrical signal as it moves across a barcode.  The scanner then measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal.

Every barcode begins with a special start character and ends with a special stop character. These codes help the reader detect the barcode and figure out whether it is being scanned forward or backward.

Some barcodes may include a checksum character just before the stop character. A checksum is calculated when the barcode is printed using the characters in the barcode. The reader performs the same calculation and compares its answer to the checksum it read at the end of the barcode. If the two don't match, the reader assumes that something is wrong, throws out the data, and tries again.

The Benefits of Using Barcodes

Improve Operational Efficiency
Since barcodes permit faster and more accurate recording of information, work in process can move quickly and be tracked precisely. Quite a bit of time can be spent tracking down the location or status of projects, folders, instruments, materials, or anything else that moves within an organization. Barcodes can help you keep better track so you can save time and respond more quickly to inquiries and changes.

Save Time
Depending on the application, time savings can be significant. Often the most dramatic examples involve the beloved chore of taking inventory. One customer needed a crew of 25 employees working over a weekend to take the 6-month inventory; with barcodes this was reduced to 4 employees and a total of about 5 hours. Even in routine day-to-day operations the time savings of barcodes add up and improve productivity. Consider a shipment of 10 cartons; it will take approximately 2 minutes or more to write down product codes and serial numbers compared to about 10 to 20 seconds to scan the barcodes. In a busy operation this can be a significant saving.