There's some escape sequences involved, but the most puzzling part is that if you compare the output for the two different barcodes, there's no obvious way on how they map.

By the way, these sequences are even showing up on Windows: Running

    perl -p -e 1
[download]

and operating the barcode reader will also display them, and not the barcode numbers. It's just that applications like Notepad seem to interpret them in a certain way so that they're showing as regular characters within the application.