UPC

UPC stands for "Universal Product Code", which was the original barcode used in the United States and Canada. The UPC (now officially EAN.UCC-12 is a numerical method of identifying products without redundancy worldwide for all types of products in the retail sector. The EAN is a superset of the original UPC increasing the digits to 13 with the prefix 0 reserved for UPC. As of 2005, manufacturers are only allowed to use the new 13-digit codes on their items, rather than having two separate numbers.

There are many more sources of information regarding the makeup of the formatting. Some of which can be found here: http://en.wikipedia.org/wiki/Universal_Product_Code

Also see a proposed method with examples on an interim inclusion of this information to a release here on the ReleaseAnnotationStyle page.

An example at the UPC Database showing both the UPC and EAN variations of a product code displayed here, http://www.upcdatabase.com/item.asp?upc=638592505421