

GPS MAKES MOUSE GO CRAZY

Here's the problem:

Part of the Windows Plug and Play module is to look for a mouse plugged into a serial port. NOTE: I havent seen a serial mouse in about ten years :-).

Windows does this by looking for constant activity on the serial port, a tell tail sign of a mouse plugged into the port. Guess what a GPS does?

Although I've seen several temporary fixes for this, i.e. deleting "sermouse.sys" file, etc, Ultimately, it seems like the problem reappears.  

This workaround from Microsoft's web site eliminates the problem, but is a little cumbersome to implement.


THE FIX - Disable Comm Port

The name is somewhat deceiving. Windows doesn't really disable the port, it just bypasses this port when performing the plug and play search of comm ports.

The Utility does this by writing an entry into the Windows registry. This registry entry tells the Plug and Play module to 
ignore a particular serial port in its search for plug and play items that may be plugged into this particular serial port. 

Download and unzip the CRAZYMOUSE.ZIP file. This file contains the original "comdisable.msi" and a copy of their "comdisable.exe" file.

Install the Comdisable.msi. There are two problems, The Microsoft install file places this tool in the "Program Files" folder and there isn't a shortcut to the desktop. ALSO - there isn't a "PATH" to this folder.

This program must be run in the command window, since there isn't a PATH, you must either make a PATH or copy the comdisable.exe file to a location that has a PATH.

I chose to just copy the comdisable.exe file into the windows\system32 folder (There is a PATH to the system32 folder). You can either copy/paste the comdisable.exe from the program files folder, OR copy the exe file I included in the ZIP file.

READY TO RUN THE PROGRAM

OK, everything is installed and ready, but not yet, you need to know the GPS com port.

FIND THE GPS COM PORT

If you have a USB GPS unit, you need to know what COMM port is being assigned to the GPS. The problem is, when you plug the GPS in, the mouse starts going crazy, ARGH.  To temporarily fix this, go to the Windows/System32 folder and delete the file "sermouse.sys". This temporary fix will allow you to find the comm port the GPS is plugged into. Now plug the GPS in and everything will work fine, for now. The next time you reboot, the "sermouse.sys" is reloaded from the driver cache, so it reappears again,  ARGH.

You can see what comm ports are assigned by going to (WinXP) (right click my computer - PROPERTIES - HARDWARE - DEVICE MANAGER - PORTS (COMM & LPT)    You should see the comm port listed

Open a command window (START - RUN - CMD)

type "comdisable /list" to get a list of comm ports. You should see the same ports listed here.

type "comdisable /disable COMx"

Do this for any comm ports that you want to exclude from Plug and Play.

REBOOT and you will have NO MORE PROBLEMS.

Waiter







