I/O Connections

I/O Ports

This is a closer view of the input/output (I/O) connections present on the motherboard. As the illustration shows, the ports are integrated into the motherboard. There are no separate cables that connect the ports to the motherboard. The I/O panel features two PS/2 ports, two Universal Serial Bus (USB) 1.0 connectors, one parallel port, two serial ports, a Musical Instrument Digital Interface (MIDI)/Game port and audio connectors. To view the signals that are routed through each port, click the individual connectors.

PS/2 Kkeyboard and Mouse Interface

PS/2 keyboard and mouse connectors are located on the back panel of the motherboard. The keyboard and mouse may be plugged into either connector. Turn off the computer power before installing or removing a keyboard or mouse.

The +5V lines to these connectors are protected with a PolySwitch circuit which acts like a self-healing fuse, re-establishing the connection after an over-current condition is removed. While this device eliminated the possibility of having to replace a fuse, care should be taken to turn off the computer power before installing or removing a keyboard or mouse.

The keyboard controller contains the keyboard and mouse controller code, provides the keyboard and mouse control functions, and supports password protection for power on/reset. A power on/reset password may be specified in the BIOS Setup Utility.

The keyboard controller also supports the hot-key sequence CTRL+ALT+DEL for a software reset. This key sequence resets the computer's software by jumping to the beginning of the basic input/output system (BIOS) code and running the Power-On Self Test (POST).

Universal Serial Bus (USB)

The motherboard has two USB ports; one USB peripheral device may be connected to each port. Port 0 is on top, port 1 on the bottom. For more than two USB devices, an external hub may be connected to either port. Some devices may even have a throughput on the plug. The motherboard fully supports the Universal Host Controller Interface (UHCI) and uses UHCI-compatible software drivers. USB features include:

  • Self-identifying, hot pluggable peripheral devices
    • Drivers will not have to be loaded and the computer will not have to be reconfigured or restarted.
    • After plugging the USB peripheral device into the USB port, the peripheral device automatically becomes fully functional.
  • Automatic mapping of function to driver and configuration
  • Support of isochronous and asynchronous transfer types
  • Support for 127 physical devices, as long as the cumulative bandwidth demands do not exceed 12 megabits per second (Mbps)
    • This is roughly 100 times the limit of current serial busses and is wide enough to daisy-chain a printer, scanner, still camera, and removable hard disk from one port.
  • Guaranteed bandwidth and low latencies appropriate for telephony, audio, and other programs
  • Error handling and fault recovery mechanisms built into protocol
  • USB keyboards and mice are supported as legacy devices during start-up and under operating systems without USB support.

Note: Computers that have an unshielded cable attached to a USB port may not meet Federal Communications Commission (FCC) Class B requirements, even if no device or a low speed USB device is attached to the cable. Use shielded cable that meets the requirements for full speed devices.

Parallel Port

A 25-pin D-sub header is provided on the back panel for a multi-mode, bi-directional port. The parallel port operates in Compatible, standard mode, Bi-directional, PS/2 compatible, Enhanced Parallel Port (EPP) and a high speed Extended Capabilities Port (ECP) mode. EPP Mode requires a driver provided by the peripheral manufacturer to operate correctly. The parallel port can be configured in the BIOS Setup Utility.

Serial Ports

Two integrated 9-pin serial connectors are provided on the back panel. The 16450 and 16550A compatible Universal Asynchronous Receiver/Transmitters (UARTs) support data transfers at speeds up to 115.2Kbits/second in extended UART mode). Both of these ports can be configured in several different combinations in the BIOS Setup Utility.