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The KeyLargo IC implements two independent USB root hubs, each of which is connected to one of the ports on the back panel of the computer. The use of two independent hubs allows both USB ports to support high data rate devices at the same time with no degradation of their performance. If a user connects a high-speed device to one port and another high-speed device to the other, both devices can operate at their full data rates.
The two external USB connectors support USB devices with data transfer rates of 1.5 Mbps or 12 Mbps. For more information, see USB Ports.
Internally, the second port of one controller is routed to the USB signal pair on the AGP slot. The second port of the other controller is routed to the modem slot for an internal USB modem.
The USB ports comply with the Universal Serial Bus Specification 1.0 Final Draft Revision. The USB register set complies with the Open Host Controller Interface (OHCI) specification.