400 DPI Serial Mouse and the Maxir 386 (63227)

The information in this article applies to:
    Microsoft Mouse driver for MS-DOS 7.x
    Microsoft Mouse driver for MS-DOS 8.x

This article was previously published under Q63227


When you try to install a 400 PPI PS/2 serial mouse on the 9-pin serial port of a Maxir 386 machine, the mouse does not install.

This information applies to the Microsoft Serial Mouse for MS-DOS systems.


When the 400 PPI PS/2 serial mouse is installed on the 9-pin serial port as a serial mouse, it uses pins 2, 3, 4, 5, and 7 to communicate with the serial port.

The other pins in the 9-pin connector are used when the PS/2 adapter is connected to the mouse. Pin 8 of the built-in serial port, when set to a logic zero, is 1 to 2 volts higher than the voltage that would be present on an IBM-compatible serial port. When a logic 1 is present on pin 8 and the mouse is connected to a 9-pin serial port, the mouse cannot reset. This prevents the mouse from installing.

To work around this problem, do the following:

Use a 9- to 25-pin serial adapter to eliminate the signal from pin 8. To do this, you need to purchase the adapter from a local electronics store. This adapter has a 9-pin female connector on one end and a 25-pin male connector on the other end.

Once you have the adapter, perform the following steps:
    Attach the adapter you purchased to the built-in serial port of your computer.
    Attach the mouse to the 25- to 9-pin serial adapter that was supplied with your mouse.
    Attach this adapter to the 9- to 25-pin adapter that you have already attached to your computer.
The Maxir product included here is manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

Modification Type: Major Last Reviewed: 9/23/2003
Keywords: KB63227