Serial Ports
Part number NS9000

These are 16550 Universal Asynchronous Receiver Transmitter (UART) high-speed serial ports one and two as indicated in the graphic illustration above. Serial ports send and receive data one bit at a time. Serial devices such as a serial mouse, serial printers and modems may be connected to this port. You may set the port to be COM1, COM2, COM3, COM4 or Disabled with the BIOS Setup program. Be sure not to set both serial ports to use the same COM port or to set them to use the same interrupt (COM1 and COM3 both use interrupt 4; COM2 and COM4 both use interrupt 3).
NOTE: If the mouse has a mini-DIN (PS/2-style) connector, the Mouse Port must be used. Click on the hot spots for pinout information.