Microsoft KB Archive/253633

= How to Troubleshoot Modems in Windows Millennium =

Article ID: 253633

Article Last Modified on 8/6/2007

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APPLIES TO


 * Microsoft Windows Millennium Edition

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This article was previously published under Q253633



If this article does not describe your hardware-related issue, please see the following Microsoft Web site to view more articles about hardware:

http://support.microsoft.com/default.aspx/w98?sid=460



SUMMARY
This article describes procedures to help you diagnose and resolve problems using your modem in Windows Millennium Edition (Me).

NOTE: If you are searching for troubleshooting information that is not referred to in this article, please try searching the Knowledge Base again using keywords listed in the following article:

242450 How to Query the Microsoft Knowledge Base Using Keywords



MORE INFORMATION
If your modem passes a diagnostics test, the problem is usually with the specific program or component you are trying to use, and not with your modem or the modem driver.

To verify whether the modem passes a diagnostics test:
 * 1) Click Start, point to Settings, click Control Panel, and then double-click Modems.
 * 2) On the General tab, verify that your modem is listed.

NOTE: If your modem is not listed, the driver is not installed properly (or is not installed at all) and your modem cannot be tested. If this is the case, install the modem driver using the steps in the "Verify Modem Type and Model" section of this article.
 * 1) Click Diagnostics, click the COM port to which your modem is attached, and then click More Info.

If the More Info dialog box appears without an error message and displays a series of at commands and responses, the modem has passed a diagnostics test.

Supported Hardware
The Windows Hardware Compatibility List (HCL) lists the devices Windows supports. To see if your modem is listed, check the HCL at the following Microsoft Web site:

http://www.microsoft.com/whdc/hcl/default.mspx

If your modem is listed, you may have an old or out-of-date modem driver. (Refer to the "Current Modem Drivers" section of this article.) If you do not have access to your modem, check the Hcl.txt file on the Windows Me CD-ROM.

Current Modem Drivers
Many modem issues are related to old or out-of-date modem drivers. You should verify that you are using the most current driver for your modem. To do so, contact the manufacturer of your modem to inquire about the availability of a new or updated modem driver. For additional information about how to locate contact information for your modem manufacturer, click the article numbers below to view the articles in the Microsoft Knowledge Base:

65416 Hardware and Software Third-Party Vendor Contact List, A-K

60781 Hardware and Software Third-Party Vendor Contact List, L-P

60782 Hardware and Software Third-Party Vendor Contact List, Q-Z

Verify Modem Type and Model
If Windows Me detects your modem but the modem still does not work, verify that your modem type and model is listed correctly:
 * 1) Click Start, point to Settings, click Control Panel, and then double-click Modems.
 * 2) On the General tab, verify that the modem listed is the correct modem.

If an incorrect modem is listed or if there is no modem listed even though Windows Me detected one, update the modem driver using the following steps:
 * 1) Click Start, point to Settings, click Control Panel, and then double-click System.
 * 2) On the Device Manager tab, double-click the Modem branch to expand it.

NOTE: If the Modem branch does not exist, double-click the Other Devices branch to expand it.
 * 1) Double-click your modem.
 * 2) On the Driver tab, click Update Driver.

You can use the Windows Millennium Update Device Driver wizard to search for the best driver or display a list from which you can select the appropriate driver. If you use the Update Device Driver wizard to search for a driver, you can also specify a location for the driver. Drivers for some additional modems are included in the Drivers\Modem folder on the Windows Me CD-ROM. If the correct driver appears in Device Manager but your modem still does not work properly, troubleshoot the problem using the appropriate methods below for your modem type.

There are three basic types of modems:
 * Standard
 * Controllerless
 * Software

Standard Modem
A standard modem has the following five components:
 * Hardware telephone line interface with connectors, high-voltage transient protection, ring detectors, relays, transformers, codecs, and so on.
 * Digital signal processing (for example, V.34 signaling).
 * Modem-to-modem protocols (for example, V.42 error control, and V.42bis data compression).
 * Modem control command interpreter (for example, V.25ter and proprietary command sets).
 * Serial PC-modem interface, either a COM port (V.24), or a serial port device exposed on another bus (ISA, PC Card, PCI).

Controllerless Modem
A controllerless modem implements bulleted items 3-5 (in the list above) in a Windows driver. In contrast, a software modem implements bulleted items 2-5 (in the list above) in a Windows driver. The lower end of either driver connects to proprietary hardware through a bus-specific driver. More broadly defined, a Windows modem includes any modem that depends on a Windows driver. In particular, this group includes modems installed on Universal Serial Bus (USB). USB modems can be complete (bulleted items 1-4 in the list above), controllerless (bulleted items 1-2), or software (bulleted item 1).

It can be difficult to differentiate between a standard modem and a controllerless modem or software modem. The best way to identify your type of modem is to check the documentation included with your modem or computer (if the modem was preinstalled).

Controllerless and Software Modem Troubleshooting
Windows Me should normally detect the presence of a controllerless or software modem and add it in Device Manager. A controllerless or software modem can be undetected because of any of the following reasons:
 * The modem was previously detected (whether drivers were installed for it or not). In this case, the modem should be listed in Device Manager, and the driver can be updated using the procedure described in the "Verify Modem Type and Model" section of this article.
 * The modem drivers were installed and then removed, but some registry entries still exist. You need to remove the registry entries before the modem can be detected again. To clear some controllerless and software modem-related registry entries, use the following steps:
 * Locate the Wmremove.inf file in the Tools\Mtsutil folder on the Windows Millennium CD-ROM.
 * Right-click the file, and then click Install.
 * Restart your computer.

NOTE: If Windows Me still does not detect your modem, the Wmremove.inf tool may not have removed all the necessary registry entries. To resolve this issue, contact your hardware manufacturer to inquire about the availability of a resolution for this issue.
 * Something may be physically wrong with the modem. Contact your modem manufacturer for the correct procedure to test your Windows-only modem.

If your modem still does not work after you install the drivers, there may be a resource conflict or an issue specific to your controllerless or software modem. To determine if this is the case, refer to the "Additional Troubleshooting" section of this article.

Standard Modem Troubleshooting
Check that the modem is working correctly by testing direct communication to the COM port:  Use your Emergency Boot Disk (EBD) to restart your computer. Type the following command at a command prompt, and then press ENTER:

echo atm1l3x0dt12345 > com

NOTE:  is the serial port number to which the modem is connected.

 The modem should dial the touch tone digits "12345." Hang up the modem by typing the following command:

echo ath0 > com

 Remove your EBD, and then restart your computer.

The atm1l3x0dt12345 command is a signal to the modem to dial the numbers "12345." The first command (Attention) signals to the modem that it is about to receive information. m1 is a universal command to turn the modem's speaker on if it is off by default. l3 is a universal command to raise the modem's speaker volume to the maximum level if it is at the lowest by default. x0 is a universal command that signals the modem to run the command without waiting for a dial tone (this is useful if modem and voice calls use the same phone line), and the dt12345 command instructs the modem to dial the digits 12345.

If the modem does not respond with a dial tone or communication signal, check your modem for damage.

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

Use Device Manager to determine if there is a resource conflict:
 * 1) Click Start, point to Settings, click Control Panel, and then double-click System.
 * 2) Click the Device Manager tab.

Typically, if there is a resource conflict that prevents one device from working, an exclamation point in a yellow circle is displayed next to the device. In some cases, however, a controllerless or software modem that conflicts with another device may not have an exclamation point in a yellow circle displayed next to it. In this case, you must determine if there is a conflict yourself by checking the resource settings:
 * 1) On the Device Manager tab, double-click the Modem branch to expand it.
 * 2) 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 Me. To determine the resources your modem is using, consult the documentation included with your modem.
 * 1) Note the resource settings used by your modem, and then click OK.
 * 2) 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: You can disregard hardware using the IRQ Holder For PCI Steering setting. This does not cause a resource conflict.

If another device is using any of the same settings as your modem, you either need to change the setting for that device or for 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 controllerless and software modems are Plug and Play, you should be able to change the settings for the modem using Device Manager. To do so, use the following steps:
 * 1) Double-click the Modem branch to expand it, and then double-click your controllerless or software modem.
 * 2) On the Resources tab, click to clear the Use Automatic Settings check box.
 * 3) In the Setting Based On box, click a basic configuration with settings that do not conflict with any other device.

NOTE:If none of the available basic configurations have settings that do not conflict with any other device, you may need to change some resource settings manually. To do so, click the last available basic configuration, double-click the resource setting you need to change, click OK, and then click OK.

COM Port Detection
If you suspect the issue is with your COM port, check for conflicts in Device Manager:  Click Start, point to Settings, click Control Panel, and then click System.</li> On the Device Manager tab, double-click the Ports (COM & LPT) Modem branch to expand it.

NOTE: If a communications port is not listed, your COM port has not be detected. To install a COM port:  Click Start, point to Settings, click Control Panel, double-click Add New Hardware.</li> Follow the instructions on your screen to detect the COM port.</li></ol> </li> On the Resources tab, click to clear the Use Automatic Settings check box.</li> In the Setting Based On box, click a basic configuration with settings that do not conflict with any other device.

NOTE: If none of the available basic configurations have settings that do not conflict with any other device, you may need to change some resource settings manually. To do so, click the last available basic configuration, double-click the resource setting you need to change, click OK, and then click OK.</li></ol>

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Keywords: kbdialup kbfaq kbhardware kbinfo kbprod2web kbtshoot KB253633

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