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

Last reviewed: September 18, 1996
Article ID: Q138159

The information in this article applies to:

Microsoft Windows 95

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:

   ARTICLE-ID: Q130402
   TITLE     : Device Contention in Windows 95

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

KBCategory: kbenv kb3rdparty
KBSubcategory: win95 wincomm dun
Additional reference words: 95 comxautoassign

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Last reviewed: September 18, 1996
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