Dell Dimension XPS 50 Reference Manual page 142

B-8 Dell Dimension XPS Txxx and Txxxr Systems Reference and Troubleshooting Guide
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Serial port A Configures the serial port. Set this option to Auto (default),
Enabled, or Disabled. If set to Enabled, you can set the fol-
lowing additional options:
Base I/O Available I/O addresses are COM1, COM2, COM3, and
COM4.
Address
Interrupt Available interrupts are IRQ3 and IRQ4.
NOTE: The Glossary in the system Help defines abbreviations and acronyms.