Chapter 2. System Board Features
USB Interface
The Intel PIIX4 chipset module contains the controller for the USB interface in IntelliStation M Pro
computers. (Refer to “Chip Set Control” on page 7 for information on the PIIX4 module.) Two USB ports
are provided on the rear connector panel of the computers. A USB-enabled device can be attached to
each port, and if that device is a hub, multiple peripheral devices can be attached to the hub and be used
by the system. Plug and Play technology is used to recognize installed devices. The USB port functions
at speeds of up to 1.5 Mbits per second or 12 Mbits per second. Data is transferred in either
asynchronous or synchronous mode. The system does not support a keyboard attached to either of the
USB ports as a boot device.
The USB is compliant with
Universal Host Controller Interface Design Guide 1.0. Features provided by
USB technology include:
Support for up to 127 physical devices
Connections of up to five meters in length from host to hub or hub to hub
Support for hot pluggable devices
Support for concurrent operation of multiple devices
Support for different device bandwidths
Guaranteed bandwidth and low latencies appropriate for telephony, audio, etc.
Wide range of packet sizes
Eight-signal USB cable
The external interface for the USB ports consists of two, 4-pin connectors. For information on connector
pin assignments, see “USB Connectors” on page 49.
Chapter 2. System Board Features
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