Dell OptiPlex Gxi - Manual (Page 36)

I/O Map: OptiPlex GXi
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