Appendix 103
IRQ Usage
The following table lists the Interrupt Request Lines (IRQs) that the system
typically uses and which ones are available for use by add-on devices.
IRQ
Resource
NMI
0
System Timer
1
Keyboard
2
Cascade
3
Serial port 2 (COM2)
4
Serial port 1 (COM1)
5
Secondary Parallel Port (LPT2)
6
Floppy Controller
7
Primary Parallel Port (LPT1)
8
Real Time Clock (RTC)
9
Cascade Redirect
10
Available
11
Available
12
PS/2 Mouse Port
13
Math Coprocessor
14
Primary Hard Disk
15
Secondary Hard Disk
4079tl.book Page 103 Tuesday, December 22, 1998 2:04 PM
