Although a surprising number of modem problems are related to phone line issues, modem failures can also be caused by incorrect settings or by damaged hardware. In this article, I’ll discuss some methods that you can use to troubleshoot these types of modem issues in Windows XP.

Checking your modem properties
Once you’ve verified the integrity of your phone line, the next step is to verify that Windows recognizes your modem and that Windows can communicate with your modem. Fortunately, Windows XP has some built-in diagnostic utilities to help you accomplish these tasks.

To diagnose your modem’s problem, open the Control Panel and click on the Performance And Maintenance link, followed by the System link. When you do, Windows will open the System Properties sheet. Select the Hardware tab and then click the Device Manager button. The Device Manager contains a list of all of the hardware devices contained within your system.

Now, navigate through the Device Manager tree until you locate your modem. Right-click on the modem and select the Properties command from the resulting context menu. Doing so will reveal the modem’s properties sheet.

On the properties sheet, check the General tab to make sure that the modem is enabled, as shown in Figure A. The General tab also contains a Troubleshooting button that you can click to launch a troubleshooting wizard that can guide you through a basic troubleshooting process.

Figure A

Be sure the volume is turned up
The next step in the process is to look at the properties sheet’s Modem tab to make sure that the modem’s volume is turned up. Being able to hear the modem during the dialing and handshaking process is often helpful. For example, on many occasions, I’ve been able to tell that there is no dial tone on the line just by listening to the dialing process. You should also check the Modem tab to make sure that the port speed is set correctly. You can see an example of this tab in Figure B.

Figure B

Query the modem
At this point, you should select the Diagnostics tab and click the Query Modem button. When you click the Query Modem button, Windows will send a series of sample commands to the modem. After a minute or two, Windows will display a summary of the commands that have been issued and the results of the commands, as shown in Figure C. You should look through the list of commands for any errors that may appear in the Response column. If errors do show up, it could be a hardware conflict, a damaged modem, or an invalid device driver.

Figure C

Resolving a hardware conflict
If you suspect a hardware conflict, the next place to check is the Resources tab. Most of the time, if the modem is conflicting with another hardware device, there will be a reference to the conflict on the Resources tab. In addition to telling you which other hardware device the modem is conflicting with, the Resources tab will also tell you which resources (such as IRQ and Base Memory Address) are conflicting. On some systems, you can resolve such a conflict by deselecting the Use Automatic Settings check box. After doing so, you’re free to select the conflicting resource and then use the Change Setting button to assign a new set of resources to the modem. Just keep in mind that not all available resources will work with all modems. It’s usually better to let Windows XP select its own resources if at all possible.

Are you a modem guru?

Do you have a handy modem troubleshooting tip or trick? Share it with your fellow TechRepublic members by posting a comment to this article.

For more information about modems, check out these other TechRepublic articles: