DOCUMENT:Q82407  30-OCT-1999  [win95x]
TITLE   :Vistacom Problems When Switching COM Ports
PRODUCT :Microsoft Windows 95.x Retail Product
PROD/VER:WINDOWS:3.0,3.0a,3.1,3.11
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 
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SUMMARY
=======

Under Microsoft Windows, Vistacom and its associated terminate-and-stay-
resident (TSR) program, DEVLOAD.EXE, can cause interrupt request line (IRQ)
conflicts when running in 386 enhanced mode.

Disabling the Combuff device in the Windows SYSTEM.INI file corrects this
problem.

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

Vistacom is a terminal emulator manufactured by Control Data. Vistacom can cause
interrupt conflicts when you disconnect from a COM port and then try to use
another COM port on the same IRQ while running in a Windows virtual machine. For
example, disconnect from COM3 and then try to use COM1. Under the standard IBM
serial port configuration, COM1 and COM3 use the same interrupt (IRQ 4).

To correct this problem, disable the Combuff device in the Windows SYSTEM.INI
file. In the [386enh] section of the SYSTEM.INI, either set the line
"COMxBuffer=0" (where "x" is the COM port number) or remove the line
"device=*combuff".

Vistacom is manufactured by a vendor independent of Microsoft; we make no
warranty, implied or otherwise, regarding this product's performance or
reliability.


Additional query words: 3.10 3.1 3.11

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Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311
Version           : WINDOWS:3.0,3.0a,3.1,3.11

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