Telkonet Inc (fka TKO)

[ETA]

Nearly all point of sale systems use ethernet these days.
This is not groundbreaking, I'd encourage you not to overreach on this one item. It has NOTHING to do with financial transactions, and to be blunt, there aren't "many other functions" of their hardware. It's a PLC based ethernet bridge. Anywhere you have electrical wiring and ethernet communications you can use Telkonet.