Why does my modem say "Can't open Port"?

Question

When I go to control panel and click modem then diagnostic then click on more info it say "Can't open port."

Answer

This question was answered on July 14, 1999. Much of the information contained herein may have changed since posting.

The following solution is taken from the Microsoft Tech support page hopefully you will find your solution here.

When you try to use your modem, you may receive the following error message:

Could not open port

This error message is typically the result of a resource conflict or a program loading from the StartUp folder that opens a communication port Use the troubleshooting steps in the "Resource Conflicts" section later in this article to resolve this error message To temporarily disable programs in the StartUp folder, follow these steps:

Click Start, point to Programs, point to Accessories, point to System Tools, and then click System Information

On the Tools menu, click System Configuration Utility

Click the Startup tab For programs that may control your modem, click the programs's check box to clear it If you are unsure whether or not a specific program should be disabled, click to clear all of the check boxes except for the following check boxes:

ScanRegistry

SystemTray

LoadPowerProfile

TaskMonitor

If your modem is set to use the same resources as another device in your computer, there is resource conflict, and either or both of the devices may not work Resource settings a standard modem uses include an input/output (I/O) address and interrupt request (IRQ) In addition to these, Windows-only modems also frequently use a direct memory access (DMA) setting

Use Device Manager to determine if there is a resource conflict To do so, follow these steps:

Click Start, point to Settings, and then click Control Panel

Double-click System, and then click the Device Manager tab

Normally, if there is a resource conflict that prevents one device from working, an exclamation point in a yellow circle is displayed for the device In some cases however, a Windows-only modem that conflicts with another device may not have an exclamation point in a yellow circle In this case, you must determine if there is a conflict yourself

To view the resource settings used by your modem, follow these steps:

On the Device Manager tab, double-click the Modem branch to expand it

Double-click your modem, and then click the Resources tab

NOTE: If the Resources tab does not exist, your modem's resources cannot be configured by Windows 98 To determine the resources your modem is using, consult the documentation included with your modem

Note the resource settings used by your modem, and then click OK

Double-click Computer to view all the resource settings in use on your computer, listed by resource Click each resource setting to determine if there is another device using any of the same settings your modem is using

NOTE: Hardware using the IRQ Holder For PCI Steering setting can be disregarded This does not cause a resource conflict

If there is another device using any of the same settings as your modem, you need to change the setting for that device or your modem If the device is a Plug and Play device, you may be able to do this on the Resources tab in Device Manager, although some devices may require you to change jumper pins or dip switches on the device itself To determine the best way to change resource settings for the device, consult the documentation included with the device or your computer

Because Windows-only modems are Plug and Play, you should be able to change the settings for the modem using Device Manager To do so, follow these steps:

Double-click the Modem branch to expand it, and then double-click your Windows-only modem

On the Resources tab, click the Use Automatic Settings check box to clear it

In the Setting Based On box, click a basic configuration with settings that do not conflict with any other device

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Author

Posted by Ken of Data Doctors on July 14, 1999