PC Hardware A Beginner’s Guide

Checking Out IRQ Settings

Not every PC has all of the devices listed in Table 13-1. In fact, on any PC, the IRQs can be

assigned differently. To find what the IRQ settings are on a Windows PC, use the follow-

ing steps:

1. From the Windows Desktop, right-click the My Computer icon. From the shortcut
   menu that appears, choose Properties to display the System Properties window,
   shown in Figure 13-1.


2. Select the Device Manager tab. Highlight the Computer entry and click the
   Properties button located at the bottom of the device window. This displays
   the Computer Properties window, shown in Figure 13-2.


3. Select the View Resources tab and click the Interrupt Request (IRQ) radio
   button to display the IRQ assignments on your PC.

(^284) PC Hardware: A Beginner’s Guide
IRQ Assignment
0 System timer
1 Standard keyboard
2 Programmable interrupt controller (PIC)
3 Serial ports 2 and 4 (COM2 and COM4)
4 Serial ports 1 and 3 (COM1 and COM3)
5 Standard sound card
6 Floppy disk controller (FDC)
7 Parallel port (LPT1)
8 CMOS and real-time clock (RTC)
9 Hardware MPEG
10 Modem audio
11 VGA video card
12 PS/2 mouse
13 Math coprocessor/numeric data processor
14 Primary IDE controller
15 Secondary IDE controller
Table 13-1. Typical IRQ Assignments