LOL, you'd be amazed how complex, yet how simple these machines are. If you picture 6 network-type jacks on a plate, for two plates (total of 12 jacks), that's the "Gilbarco" card. It's actually called a G-stop card. It controls stuff like the little readout that has the item name/price on it, the keyboard, the reciept printer, barcode scanner, drawer, credit card scanner, and a couple other things, as well as the uplink. It also controls the pump controller. All of this is off of RS485/RS232 (serial).
What tops it all off is, it's on a full-length ISA (legacy) card. And, it's supposed to be bootable, like a network bootup. Why it doesn't boot, is beyond me. All I know is, it's the first time I've seen a celeron 533 with just a floppy in it. No CD, no HD, just the floppy.
Trust me, it's enough to cause your frontal lobe to spontaneously collapse.