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Q161516: Troubleshooting Modem Problems Under Windows NT 4.0

Article: Q161516
Product(s): Microsoft Windows NT
Version(s): winnt:4.0
Operating System(s): 
Keyword(s): kbhw kbHardwarekbfaq
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server version 4.0 
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SUMMARY
=======

This article describes procedures to help you diagnose and fix problems when you
are unable to dial out using your modem in Windows NT 4.0 with Dial-Up
Networking (DUN).

MORE INFORMATION
================

Installing Your Modem
---------------------

If your modem is not on the Windows NT 4.0 Hardware Compatibility List (HCL) or
is not detected by Windows NT, use one of the following procedures to install
it:

- Obtain from the modem manufacturer an .inf file designed for Windows NT 4.0.
  Follow the manufacturer's instructions for installing the modem in Windows NT
  4.0. Contact the modem manufacturer for assistance with this procedure.

- If your modem has an .inf file for Windows 95, you may be able to use that
  file under Windows NT. When you are adding the modem through Control Panel,
  Modems, check the box labeled, "Don't detect my modem; I will select it from
  a list." Choose the "Have Disk" option and insert the disk containing the
  Windows 95 .inf file. Please be aware that not all Windows 95 .inf files will
  work correctly in Windows NT 4.0.

- Install your modem as a standard modem using the following steps:

  1. In Control Panel, double-click Modems. The Install New Modem Wizard starts
     automatically if you have not installed a modem before. If the wizard does
     not start automatically, you have installed a modem previously and you
     should click Add to start the wizard.

  2. Check the box labeled "Don't detect my modem; I will select it from a
     list," and then click Next.

  3. In the Manufacturers box, click Standard Modem Types. In the Models box,
     click a model that corresponds to the speed of your modem, and then follow
     the instructions in the Install New Modem Wizard.

Verify Your COM Port(s)
-----------------------

Verify that Windows NT recognizes your COM port(s) by double-clicking the Ports
icon in Control Panel to see if the COM port that the modem is connected to is
listed. If it is, Windows NT recognizes the COM port.

If the COM port is not recognized in the Control Panel Ports applet, there is
most likely a hardware problem or a configuration problem. Use the following
steps to troubleshoot the problem.

External Modems

1. If the COM port is on the motherboard or is provided by a serial card, make
  sure the port is not disabled in the BIOS (also called the CMOS) setup of the
  computer. Refer to the documentation for your computer to obtain information
  about configuring options in the BIOS setup.

2. Make sure there are no other adapters or devices that are configured for the
  same Base I/O Address or IRQ as the COM port to which the modem is attached.

3. Verify that the serial port is not defective. If the modem and any other
  serial devices fail on the COM port but work on other COM ports, and you have
  verified the two steps above, the serial port may be defective.

4. Verify the serial cable is not defective by using a new standard serial
  cable.

Internal Modems

1. If the COM port is defined by an internal modem, make sure the jumpers on the
  modem are configured properly. Internal modems will almost always have a
  jumper on the adapter that configures the modem as a particular COM port.
  There may or may not be jumpers that allow you to set the Base I/O Address
  and IRQ to be used by the modem as well.

2. If the modem is configured for a COM port number that is assigned to a COM
  port on the motherboard or a serial card (physical port), you must either set
  the modem to use a different COM port, or use the BIOS setup to disable the
  COM port with the same number as the internal modem. For example, if both the
  internal modem and the physical COM port are set to COM1, you must either set
  the internal modem to a different, unused COM port, or the physical COM1 port
  must be disabled in the BIOS setup.

3. Make sure there are no other adapters or devices that are configured for the
  same Base I/O Address or IRQ as the internal modem. Usually COM3, using an
  IRQ (or interrupt) of 5, is a good choice for an internal modem. However, if
  you have a sound card, you may need to choose a different IRQ than 5 since
  many sound cards use that interrupt.

4. In the Ports component of Control Panel, verify that the IRQ settings and the
  I/O addresses are correct. Check the System log with the Event Viewer for I/O
  or IRQ conflict errors.

  When possible, use standard settings for COM ports, which are as follows:

        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

5. You do NOT need to add a new port in the Control Panel Ports applet to add
  support for an internal modem. NTDETECT will detect the internal modem and
  the COM port it is configured to use. If a duplicate port was added using the
  Add button in the Control Panel Ports applet, use the Delete button to remove
  the duplicate port.

6. Verify that the internal modem is not defective. Also, it is often a good
  idea to check with the vendor of your modem to see if there is a flash
  upgrade available for your modem.

Troubleshoot with HyperTerminal
-------------------------------

Verify that Windows NT recognizes your modem and that you can dial out using the
HyperTerminal program. To do so, follow these steps:

NOTE: Before attempting to use HyperTerminal, verify that the Remote Access
Server service is not running. Double-click the Services icon in Control Panel
and verify that the Status column next to Remote Access Server is blank. If it
displays "Started," click the Stop button to disable the Remote Access Server
service before continuing.

1. Click Start, point to Programs, point to Accessories, point to HyperTerminal,
  and then click HyperTerminal.

2. When the New Connection Wizard is displayed, click Cancel.

3. On the File menu, click Properties, and then click the modem you want to test
  to select it in the Connect Using list.

4. Click Configure, verify that your modem is set to use the correct port, and
  then click OK.

5. Type "AT" (without quotation marks) in the HyperTerminal window, and then
  press ENTER.

6. If "AT" (without quotation marks) is displayed in the HyperTerminal window as
  you type it and "OK" (without quotation marks) is displayed after you press
  ENTER, HyperTerminal recognizes the modem properly. If "AT" is not displayed
  as you type it or if "OK" is not displayed after you press ENTER, review the
  previous steps in this article to verify that your modem is installed
  properly in Windows NT.

7. Verify that your modem can dial out using HyperTerminal. On the File menu,
  click New Connection, and then follow the instructions on your screen.

8. Click Dial. If the modem's speaker is enabled, you should hear a dial tone
  and the sound of the modem dialing the phone number.

For additional information, please see the following article(s) in the Microsoft
Knowledge Base:

  ARTICLE-ID: Q131868
  TITLE : Troubleshooting PCMCIA Modems in Windows NT 3.51

  ARTICLE-ID: Q150808
  TITLE : Disabling Remote Access Support for Unimodem Modems


Additional query words: connecting ras dialin tshoot

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Keywords          : kbhw kbHardware kbfaq
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : winnt:4.0

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