Q138159: 16-Bit MS-DOS-Based Communications Program May Not Work

Article: Q138159
Product(s): Microsoft Windows 95.x Retail Product
Version(s): 95
Operating System(s): 
Keyword(s): dun win95 kbDialUp
Last Modified: 28-JUL-2001

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The information in this article applies to:

- Microsoft Windows 95 
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SYMPTOMS
========

When you try to use a 16-bit MS-DOS-based communications program in an MS-DOS
session in Windows 95, the modem may not be initialized properly. When this
occurs, you may receive an error message stating that the communications port is
in use, not found, or unable to initialize.

In some cases, no error message is displayed, but you cannot use the modem in the
16-bit communications program.

CAUSE
=====

This behavior can occur if Dial-Up Networking Server is monitoring the line, if
your fax modem is set to receive faxes automatically, or if the modem is using
the wrong IRQ or I/O address for the COM port.

RESOLUTION
==========

To resolve this issue, add the following setting to the [386Enh] section of the
System.ini file

  COM<n>AutoAssign=2

where <n> is the port your modem is assigned to. For example:

  COM2AutoAssign=2

If the "COM<n>AutoAssign=2" setting does not work, close all programs that
are monitoring the communications port (such as Dial-Up Networking Server and
Microsoft Fax), and then use one of the following methods:

- Disable caller access to Dial-Up Networking Server. To do so, follow these
  steps:

  1. Click the Start button, point to Programs, point to Accessories, and then
     click Dial-Up Networking.

  2. Click Connections, and then click Dial-Up Server.

  3. Click No Caller Access, and then click OK.

- Disable the automatic receiving of faxes. To do so, follow these steps:

  1. Use the right mouse button to click Inbox on the desktop, and then click
     Properties on the menu that appears.

  2. Click Microsoft Fax, and then click Properties.

  3. Click Modem, click the modem you are using, and then click Properties.

  4. Click Don't Answer, and then click OK until you return to the desktop.

For additional information about using the "COM<n>AutoAssign=" setting,
please see the following article in the Microsoft Knowledge Base:

  Q130402 Device Contention in Windows

Also, verify that the modem is using the correct IRQ and I/O address settings for
the COM port it is using.

Additional query words: comxautoassign

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Keywords          : dun win95 kbDialUp 
Technology        : kbWin95search kbZNotKeyword3
Version           : 95

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