I quickly found this one... till this post, I've never thought about how bar codes work. :D https://www.abr.com/wp-content/uploads/2014/04/barcode-basics.pdf h

I quickly found this one... till this post, I've never thought about how bar codes work. :D https://www.abr.com/wp-content/uploads/2014/04/barcode-basics.pdf https://www.abr.com/wp-content/uploads/2014/04/barcode-basic...