Epson 400, 600, 640, EX, 700, 800, 850, 1520, 3000 User Manual page 21

1 Connect the adapter to an available USB port on the back of your
computer, as shown below. If you're using a USB hub, plug it into an
available USB port on your computer, then plug the adapter into a USB
port on the hub. If you have more than one hub, plug the adapter into
the first hub.
USB ports
USB/Parallel Adapter
OR
USB/Parallel Adapter
16
optional
USB hub