Windows 3.1 COMM.DRV File May Be Incompatible with PS/2 50Z

• Microsoft Windows operating system versions 3.1, 3.11

SUMMARY

The Windows 3.1 COMM.DRV designed for external modems that are connected to the on board serial port (COM1) may not work with early models of the IBM PS/2 50Z. Windows may not be able to communicate with the modem, or the computer may lock up.

The following information does not apply to internal modems because they do not use the external serial port on the 50Z. They should work with Windows 3.1.

MORE INFORMATION

Early versions of the IBM PS/2 model 50Z may have shipped with ZM41 system boards that use a non-standard serial communications port.

At speeds less than 9600bps, the external (COM1) serial port may fail with Windows 3.1 and other communications programs, including Autosig for MS-DOS and the CompuServe Information Manager (CIM) for MS-DOS.

WORKAROUND

As a possible workaround, you can try using the COMM.DRV driver for Windows 3.0. If you have this driver available, install it as follows:

1. Make a backup copy of the COMM.DRV that is located in your Windows system subdirectory.

2. Insert the Windows 3.0 disk that contains COMM.DR_ into a floppy disk drive. This file is located on disk 1 (5.25-inch high-density), disk 2 (3.5-inch low-density) or disk 4 (5.25-inch low-density).

3. Use the EXPAND command to expand the file to the hard disk. For example:

         EXPAND A:COMM.DR_ c:\Windows\SYSTEM
   

The IBM products included here are manufactured by International Business Machines, Inc., a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.