UPD: New MSCOMM Control Available

ID: Q101944

The information in this article applies to:

Microsoft Visual Basic Professional Edition for Windows, versions 2.0, 3.0

SUMMARY

A new version of the MSCOMM.VBX control is available. This new control fixes a problem where the OnComm event will not fire when communicating with some 14.4K baud modems.

MORE INFORMATION

The following file is available for download from the Microsoft Software Library:

~ MSCOMM.EXE

For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:

Q119591 : How to Obtain Microsoft Support Files from Online Services

The date, time, size, and version number of the MSCOMM.VBX file that shipped with Visual Basic version 3.0 is:


   Date: 28-APR-1993
   Time: 12:00 a.m.
   Size: 34304
   Version: 2.0.9000.7

The date, time, size, and version number of the updated MSCOMM.VBX file is as follows:


   Date: 12-MAY-1993
   Time: 12:21 p.m.
   Size: 34816
   Version: 2.1.0.1

When using the MSCOMM.VBX provided with Visual Basic version 2.0 or 3.0 to communicate with a 14.4K baud modem, the OnComm event may not fire. The revised version of the MSCOMM.VBX control available fixes this problem by introducing a new Notification property. The problem relates to using Windows version 3.1 event driven communications. The new property fixes the problem by allowing you to use Windows version 3.0 polling techniques instead.

The Notification property is not available at design time, but you can get and set its property value at run time. It's default value of zero (0) tells the control to use Windows version 3.0 polling techniques. A value of 1 tells the control to use Windows version 3.1 event driven communications.

Microsoft recommends that you set the property value to 1 if you are using the MSCOMM control to communicate with a modem that has a baud rate lower than 14.4K baud.

One other change was made. The default property setting for the Interval property was changed from 1000 to 55.

Installation

To install the new control, copy the updated version to the WINDOWS\SYSTEM directory on your computer. Also check to make sure that no other copies of MSCOMM.VBX exist on your computer. If you find an older version of the MSCOMM.VBX file, delete it or rename it.
NOTE: When installing the updated MSCOMM.VBX, make sure no existing Visual Basic applications that used the original MSCOMM.VBX are broken. The updated MSCOMM.VBX (Version: 2.1.0.1) is not compatible with Visual Basic application .EXE files compiled with the original version of the MSCOMM.VBX (Version: 2.0.9000.7). These applications must be recompiled with the 2.1.0.1 version of the MSCOMM.VBX in order to work correctly with this updated .VBX file. The updated version of MSCOMM.VBX fixes a problem where the OnComm event will not fire when communicating with some 14.4 baud modems. If the specific problem fixed by the updated MSCOMM.VBX is not a concern and there are existing Visual Basic applications for which the source code is not available, use the original MSCOMM.VBX -- not the updated one.

Additional query words: kbfile update3.00 softlib S14642


Keywords          : kbVBp kbVBp300 PrgCtrlsCus kbvbp200 
Version           : WINDOWS:2.0,3.0
Platform          : WINDOWS 
Issue type        :

Last Reviewed: May 15, 1999