Studying for the A+, Network+ or Security+ exams? Get over 2,600 pages of FREE study guides at CertiGuide.com!
Join the PC homebuilding revolution! Read the all-new, FREE 200-page online guide: How to Build Your Own PC!
NOTE: Using robot software to mass-download the site degrades the server and is prohibited. See here for more.
Find The PC Guide helpful? Please consider a donation to The PC Guide Tip Jar. Visa/MC/Paypal accepted.
Take a virtual vacation any time at DesktopScenes.com - view my art photos online for FREE in either Flash or HTML!

[ The PC Guide | Systems and Components Reference Guide | Motherboard and System Devices | System Resources | Interrupts (IRQs) | IRQ Details By Number ]

IRQ3

IRQ Number: 3

16-Bit Priority: 11

Bus Line: 8/16-bit

Typical Default Use: COM2 (second serial port).

Other Common Uses: COM4 (fourth serial port), modems, sound cards, network cards, tape accelerator cards.

Description: This interrupt is normally used by the second serial port, COM2. It is also the default interrupt for the fourth serial port, COM4, and a popular option for modems, sound cards and other devices. Modems often come pre-configured to use COM2 on IRQ3.

Conflicts: Conflicts on IRQ3 are relatively common. The two biggest problem areas are first, modems that attempt to use COM2/IRQ3 and clash with the built-in COM2 port; and second, systems that attempt to use both COM2 and COM4 simultaneously on this same interrupt line. In addition, some devices, particularly network interface cards, come with IRQ3 as the default. In most cases the problem can be avoided by changing the conflicting device to a different interrupt (IRQ2 and IRQ5 usually being the best choices). If the built-in COM2 is not being used, it can be disabled in the BIOS setup, which will allow a modem to stay at COM2/IRQ3 without causing any problems. More general solutions to these issues can be found in the conflict resolution area of the Troubleshooting Expert.

Next: IRQ4


Home  -  Search  -  Topics  -  Up

The PC Guide (http://www.PCGuide.com)
Site Version: 2.2.0 - Version Date: April 17, 2001
Copyright 1997-2004 Charles M. Kozierok. All Rights Reserved.

Not responsible for any loss resulting from the use of this site.
Please read the Site Guide before using this material.
Custom Search