Troubleshooting RAS Client Issues in Windows NT
This article contains steps to help you troubleshoot issues with the
Remote Access Service (RAS) in Windows NT 4.0. This article focuses on
issues that can occur when you use RAS to dial into another computer or an
Internet service provider (ISP).
The issues discussed in this article include:
- Cannot dial with RAS
- Cannot connect after dialing with RAS
Cannot Dial with RAS
When you attempt to dial with Dial-Up Networking, the following error
message may appear:
Error 692: Hardware failure in port or attached device.
If you have upgraded from Windows NT 3.51 and you are running a program
that monitors the phone line (for example, a fax program), you may receive
an error message that indicates the port is busy when you try to dial out
with Dial-Up Networking. For example:
Error 633: The port is already in use or is not configured for Remote
Access dial out.
If you installed RAS in Windows NT 3.51 before upgrading to Windows NT
4.0, the kernel-mode telephony driver that is used in Windows NT 3.51 is
retained and RAS uses non-Unimodem drivers. If another program uses the
Unimodem driver and is set answer the line automatically, that program causes
TAPI 2.0 to control the communications port. When this occurs, the
communications port is not available to the non-Unimodem version of RAS.
To resolve this problem, remove the non-Unimodem driver and replace it
with one supplied with Windows NT 4.0. To do so, follow theses steps:
- In Control Panel, double-click Network.
- Click the Services tab.
- Click Remote Access Service, and then click Properties.
- If the type of modem listed indicates that the kernel-mode
TAPI driver is still being used [that is, it lists the type as "Modem
(modem.inf)"], click the port, and then click Remove.
- Click Add to add the Unimodem driver (the driver supplied with
Windows NT 4.0) for this COM port.
- Click Continue and restart your computer when prompted to do
Cannot Connect After Dialing with RAS
If the telephone line is unusually noisy, you may receive an error message
Error 640: A Netbios error has occurred.
This message indicates that the modem may not be able to negotiate a
connection at a higher speed. Try setting the modem speed on the client
computer down to a lower speed such as 9600 bps. To do so, follow these
If the RAS server does not answer or you cannot connect, test the
connection from another computer. If you cannot connect using another
computer, there may be a problem with the RAS server. Contact your network
administrator for assistance.
- In Dial-Up Networking, click the appropriate phone book entry.
- Click More, and then click Edit Entry And Modem Properties.
- Click the appropriate modem, and then click Configure.
- In the Initial Speed box, click 9600, and then click the
Enable Modem Compression check box to clear it.
- Click OK.
- Click the Server tab, click the Enable Software Compression
check box to clear it, and then click OK.
If you can connect to the RAS server from another computer, there may be a
hardware compatibility problem with your modem. Check the Windows NT
Hardware Compatibility List (HCL) to see if your modem is listed. If your
modem is not listed, contact the modem's manufacturer or consider trying a
Provided by Microsoft