Most of the bar codes we see around us are just a sequence of untyped bytes, the reader might infer their meaning based on the encoding (carrier), or by looking at the bytes – if the content starts with
http, it probably is a url.
One example of structured bar code is GS1’s expanded Databar. The code is segmented in various fields, whose type is identified by a number. If you look at the bar code in the image, it contains the following fields:
|02||04049500673266||GTIN of the item in the package|
|17||200630||Expiration data, 30th of June 2020, not 2006.|
|37||20||Count of Trade Items. The box actually contains 100 pieces.|
What is interesting is that this product has a PZN, the german medical product identifier, with number 06453501, this number could have been encoded in the Databar, with application/type code