UPC Codes
 

They amaze me.

How do they not get duplicated - they are so prevalent, and yet they never seem to repeat. Is there a master clearing house somewhere? Are you allotted certain ranges? How do they prevent duplicates?

Yep, you lease/buy certain ranges from an overall list.

Some people then sub-lease or loan their numbers and keep track of them themselves.

I think our range at work is about 100, so we just have a small db table we have kicking around to pick the next in line not reuse them.

a manufacturer requests a certain UPC code range. then that manufacturer is responsible for tagging their items with UPC

1st digit is case container size indicator
digits 2-7 are the mfgr code. (1 mfgr can have multiple sets of these)
digits 8-13 is product code
digit 14 is checksum

6 digits for mfgr's mean there can be just under a million unique manufacturers
6 digits per mfgr for 1mil products/mfgr code.

1 trillion total combinations

What happens if you "steal" a code. Let's say that you sell widgets and you take a code from a gegaw that will never be sold in your industry?

Why would you do this?

Its been a long time since I had to get a UPC code, but I recall it wasn't expensive.

iirc I paid ~$700 for a hundred. ...plus a small annual fee. You would have to have a special system to assign price info on the read side.

IOW, you would have your own internal codes that happen to look just like GS1's system. ...but that won't work if you are reselling to a distributor or point of sale. (they like having one standard)

FWIW, I expect that computer vision will soon displace bar codes. That is, bar codes are just a crude way for the machine to recognize the product. ...the machines are getting smarter. ;)