Dell OptiPlex GX1p User Manual page 18

I/O Map: Dell™ OptiPlex™ GX1p
Address Device
0000-000F DMA controller #1
0020-003F Interrupt controller #1
0040-0043 System timers
0044-005F Reserved
0060-006F Keyboard controller
0070-0071 RTC and NMI enable
0080-008F DMA page registers
00A0-00BF Interrupt controller #2
00C0-00DF DMA controller #2
00F0 Coprocessor busy clear
00F1 Coprocessor busy reset
00F2-00FF Available
278-27F LPT2
2E8-2EF COM4
2F8-2FF COM2
378-37F LPT1
3E8-3EF COM3
3F8-3FF COM1