An extension device for connecting one or more peripheral devices to a computer, comprising a first bus for connecting to the computer; a second bus for connecting to the computer; a hub coupled to the first bus for connecting the computer to one or more peripheral devices; a controller for connecting the computer to a high-bandwidth device, the controller being switchably coupled to the hub and the second bus; and a switch for switching the controller, from being coupled to the hub, to being coupled to the second bus, when a connection to the computer is detected on the second bus.