It's important to remember for yourself what the product code (part number, a unique identifier) and a barcode – a completely different concept, and, in general, no relation to each other have not. Understanding this difference is easy to explain why one item (item) can have several different bar codes – any additional information that the provider sees fit to provide (color, batch number, weight, price, etc.), it encodes using the black and white stripes and puts the goods and / or packaging. How, then, when reading the scanner, the user system understands that a number of different bar codes mean the same heading? This should take care who fills the system database. Usually, it is hard to do. For example, this could look like card product for the Nokia 3720 in the program 1C: Managing commercial enterprise (on the left bar codes – how they look on the box and labels to the right – product information to the operator's screen): The image makes it clear that Nokia phones 3720, with which the organization is concerned: there is a part number 6438158055094, designated by the manufacturer to identify all the phones of this model, individual instances of different color and a unique number IMEI.
This fact denote the two sets of numbers: the code assigned 2000090001398 gray phone with IMEI 355441034567385, 2000090001404 assigned code yellow with IMEI 355241034545385. To the knowledge of the peculiarities of the goods have been available outside of the computer and database, these sets of numbers printed directly on a product (or packaging). And print it as a barcode, so you can all read it fast scanner. As a result, for one specific phone have a barcode indicating the model, and barcode with his characteristics – EMEI and color. To complete the picture, you can add a third bar code with information about the package (container) and the fourth – with transport marks.