system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do barcodes work when the same item is sent to different places with different register systems, different prices assigned, etc.?
gpt
The bar code is just another way of writing a number, which is also printed directly below the barcode.

What happens is that the manufacturer says "this bar code number corresponds to this product," and all of the stores list it in their systems under that number.

It doesn't communicate any information about price, however. So the store is free to assign "UPC X = $Y" in their own system totally independently of any other store's systems.