The ISP1561 is a PCI-based, single-chip Universal Serial Bus (USB) Host Controller. It integrates two Original USB Open Host Controller Interface (OHCI) cores, one Hi-Speed USB Enhanced Host Controller Interface (EHCI) core and four transceivers that are compliant with Hi-Speed USB and Original USB. The functional parts of the ISP1561 are fully compliant with Universal Serial Bus Specification Rev. 2.0, Open Host Controller Interface Specifications Rev. 1.0a, Enhanced Host Controller Interface Specification for Universal Serial Bus Rev. 0.95, PCI Local Bus Specification Rev. 2.2 and PCI Bus Power Management Interface Specification Rev. 1.1. The integrated high performance USB transceivers enable the ISP1561 to handle all Hi-Speed USB transfer speed modes: high-speed (480 Mbit/s), full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s). The ISP1561 provides four downstream ports that enables simultaneous connections of USB devices at different speeds. The ISP1561 provides three downstream port status indicators—GoodLink™ along with green and amber LEDs—to allow user-rich messages of the Root Hub downstream ports status, without requiring detailed port information to be reflected in the internal registers. The ISP1561 is fully compatible with various operating system drivers, such as Microsoft® Windows® standard OHCI and EHCI drivers that are present in Windows 98 Second Edition (SE)