The ISP1521 is a stand-alone Universal Serial Bus (USB) hub controller IC that complies with Universal Serial Bus Specification Rev. 2.0. It supports data transfer at high-speed (480 Mbit/s), full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s). The upstream facing port can be connected to a Hi-Speed USB host or hub or to an Original USB host or hub. If the upstream facing port is connected to a Hi-Speed USB host or hub, then the ISP1521 will operate as a Hi-Speed USB hub. That is, it will support high-speed, full-speed and low-speed devices connected to its downstream facing ports. If the upstream facing port is connected to an Original USB host or hub, then the ISP1521 will operate as an Original USB hub. That is, high-speed devices that are connected to its downstream facing ports will operate in full-speed mode instead.