Scan Data Into Combo Box

If I had two populated combo boxes, one of them has product code and other product types/product list and wanted to scan the product code.Is it possible to scan a product code(barcode) and would that select the product code from the list if it is there,would that be the same as If I manually selected that product code,but I am just scanning it.

I am trying to let customers that have a scanner to scan the product which populates the product type according to product code scanned.,for example if I scan Victoria that selects Melbourne,if that is possible I should be fine.

But I also have to be able to let customers that don't have a scanner to select the product from the product list,which means if they have a scanner I cross reference the product code=product type if not then show all the products in the list and that is where my idea falls apart as at this point in time I am not sure how to populate all the products if no product code exists. The list of products and codes is huge.