How to Troubleshoot PCMCIA Modems in Windows NT

This article was previously published under Q131868
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This article describes how to troubleshoot a PC Card (PCMCIA) modem inWindows NT. The following topics are discussed:
  • Windows NT does not recognize the modem
  • Terminal or HyperTerminal stops responding (hangs)
  • Remote Access Service (RAS) does not function properly
  • The modem makes no sound when dialing

Windows NT Does Not Recognize the Modem

To resolve this issue, follow these steps:
  1. Verify that the PC Card modem you are trying to install is on the Windows NT Hardware Compatibility List (HCL). If the PC Card modem is not on the HCL, Microsoft has not tested it and it is not supported by Microsoft.
  2. Verify that the PC Card modem is fully inserted into the PC card socket before you turn on your computer. If necessary, turn off your computer, insert the PC Card modem into the PC Card socket, and then turn on your computer.
  3. Verify that the PC Card modem is functioning properly by using a manufacturer-provided diagnostics program or the Pcmcmd.exe support program. The Pcmcmd.exe support program displays the hardware information from the PC Card modem. If the Pcmcmd.exe support program is unable to display any hardware information for the PC Card modem, the PC Card modem may be defective.

    NOTE: The Pcmcmd.exe support program is located on the Windows NT CD-ROM in the \Support\Debug\<hardware platform> folder.
  4. In Control Panel, double-click Ports to see if an additional COM port is listed. If an additional COM port is listed, the PC Card modem is enabled. Verify that the IRQ settings and the I/O addresses are correct. Use Event Viewer to view the System log and check for I/O or IRQ conflicts.

    NOTE: If possible, use the following standard settings for your COM ports:
    SERIAL 1   COM1:  I/O Address = 3F8h   IRQ = 4SERIAL 2   COM2:  I/O Address = 2F8h   IRQ = 3SERIAL 3   COM3:  I/O Address = 3E8h,  IRQ = 4SERIAL 4   COM4:  I/O Address = 2E8h,  IRQ = 3
    Many manufacturers include a configuration program that configures the PC Card's IRQ, slot location, and sound settings. This program can be used to modify the PC Card's settings so that conflicts do not occur.
  5. In Control Panel, double-click Devices to determine if the PCMCIA driver startup is configured as Boot. The PCMCIA driver activates all PC Card devices , and if this driver does not start, no PC Card can work. If the driver is set to start automatically but does not start automatically, use Event Viewer to view the System log and check for errors.
  6. Because there are many different PC Card chipsets available, some PC Cards do not work properly with some computers. To determine if this is the case, test your PC Card in a different computer, or test a different PC Card in your current computer.

Terminal or HyperTerminal Stops Responding (Hangs)

To resolve this issue, follow these steps:
  1. Verify that Windows NT recognizes your modem by following the steps in the "Windows NT Does Not Recognize the Modem" section of this article.
  2. If first in, first out (FIFO) is not supported by your PC Card modem, you must disable FIFO. To do so, follow these steps:

    1. In Control Panel, double-click Ports, click Settings, click the port that your PC Card modem is configured for, and then click Settings.
    2. Click Advanced, click the FIFO Enabled check box to clear it, click OK, and then restart your computer when you are prompted to do so.

Remote Access Service (RAS) Does Not Function Properly

To resolve this issue, follow these steps:
  1. Verify that the Terminal or HyperTerminal program functions properly. If your PC Card modem works with these programs, verify that the modem type is being detected correctly, and that the speed setting is correctly configured.
  2. If you experience dropped connections or noisy phone lines, lower your modem's connection speed and then test to see if the issue is resolved.
  3. Verify that your phone cable is functioning properly by using a different cable, and then test to see if the issue is resolved.
  4. Change the Logging value in the following registry key to 1:
    Restart your computer, try to connect again, and then view the Device.log file in the %SYSTEMROOT%\SYSTEM32\RAS folder for information about commands that the modem is sending and errors that are reported.

The Modem Makes No Sound When Dialing

To resolve this issue, follow these steps:
  1. Consult the manufacturer's documentation or contact the manufacturer to verify that your modem normally makes a dialing sound. Some modems emit a series of clicks when waiting for a dial tone, dialing, or waitingfor an answer.
  2. To verify that your modem's speaker is not disabled, consult the modem manufacturer's documentation. On some modems, the speaker is disabled by default.

    NOTE: The AT command "AT M1" (without the quotation marks) usually enables the modem speaker.

Article ID: 131868 - Last Review: 01/09/2015 05:18:54 - Revision: 1.1

Microsoft Windows NT Server 3.51, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Workstation 3.51, Microsoft Windows NT Workstation 4.0 Developer Edition

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