How to Troubleshoot PCMCIA Modems in Windows NT
Summary: This article describes how to troubleshoot a PC Card (PCMCIA)
modem in Windows 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.
More Information:
To resolve this issue, follow these steps:
- 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.
- 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.
- 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\ folder.
- 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 = 4
SERIAL 2 COM2: I/O Address = 2F8h IRQ = 3
SERIAL 3 COM3: I/O Address = 3E8h, IRQ = 4
SERIAL 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.
- 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 automatical ly but does not start automatically,
use Event Viewer to view the System log and check for errors.
- 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:
- Verify that Windows NT recognizes your modem by following the steps in
the "Windows NT Does Not Recognize the Modem" section of this article.
- If first in, first out (FIFO) is not supported by your PC Card modem,
you must disable FIFO. To do so, follow these steps:
- In Control Panel, double-click Ports, click Settings, click the port
that your PC Card modem is configured for, and then click Settings.
- 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:
- 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.
- 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.
- Verify that your phone cable is functioning properly by using a
different cable, and then test to see if the issue is resolved.
- Change the Logging value in the following registry key to 1:
WARNING: Using Registry Editor incorrectly can cause serious,
system-wide problems that may require you to reinstall Windows NT to
correct them. Microsoft cannot guarantee that any problems resulting from
the use of Registry Editor can be solved. Use this tool at your own risk.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan \Parameters
- To start Registry Editor click on Start then Run and in the Open field
type in "regedit".
- 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:
- 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 waiting for an
answer.
- 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.
Provided by Microsoft
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