Intel LGA775 - Manual (Page 64)

APPENDIX
B. Interrupt Request Lines (IRQ)
Peripheral devices use interrupt request lines to notify CPU for the
service required. The following table shows the IRQ used by the devices
on board.
Level Function
IRQ0 System Timer Output
IRQ1 Keyboard
IRQ2 Interrupt Cascade
IRQ3 Serial Port #2
IRQ4 Serial Port #1
IRQ5 Reserved
IRQ6 Floppy Disk Controller
IRQ7 Parallel Port #1
IRQ8 Real Time Clock
IRQ9 Reserved
IRQ10 Reserved
IRQ11 Reserved
IRQ12 PS/2 Mouse
IRQ13 80287
IRQ14 Primary IDE
IRQ15 Secondary IDE
60 2801550 User’s Manual