Knowledge Base

When Windows 2000 or XP is started while GPS data is coming into a serial port, Windows may think it is data coming from a mouse and use the GPS data to control the cursor.  This causes the cursor to erratically jump around the screen.

If there is a third-party serial mouse driver installed, it could also interpret the GPS data as mouse data.  If this is the case, go to Control Panel -> System -> Hardware -> Device Manager and disable the third-party serial mouse driver.  Do not disable other mouse drivers that do not use the serial port, such as touchpad, touchscreen or USB mice.  For example, if you installed the Logitech Mouseware V8.0 for a Trackman Marble, you must also disable the "Logitech Serial Mouse" device, called "lsermous" 

Instructions for disabling the detection of serial devices are available at http://support.microsoft.com/kb/131976/EN-US/  The text of that web page is copied here for your convenience.

SUMMARY
This article explains how to modify the Boot.ini file to disable the detection of devices on COM ports. 

When you start Windows NT, NTDETECT searches for the pointing device (usually a mouse). In the course of this process, data is sent to the serial (COM) ports. If a serial mouse is detected, Windows NT disables the port so a device driver for the mouse can load instead. If a device is not detected, Windows NT disables the port. A disabled COM port does not display any information in Control Panel Ports. 

MORE INFORMATION
To disable the detection of devices on COM ports in Windows NT: 
1.	Make a backup copy of the Boot.ini file. 
2.	Remove the hidden, system, and read-only attributes from the Boot.ini file. 
3.	Using a text editor (such as Notepad) open the Boot.ini file. 
4.	Add the /NoSerialMice option to the end of each entry in the [operating systems] section of Boot.ini. See the example below for more information. 
5.	Save Boot.ini and quit Notepad. 
6.	Restore the hidden, system, and read-only attributes to the Boot.ini file. 
7.	Shutdown and restart Windows NT. 

The following is a sample of the Boot.ini file: 

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[boot loader] 
timeout=3 
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT35 

operating systems] 
multi(0)disk(0)rdisk(0)partition(1)\WINNT35="Windows NT Workstation Version 3.51" /NoSerialMice 

multi(0)disk(0)rdisk(0)partition(1)\WINNT35="Windows NT Workstation Version 3.51 [VGA mode]" /basevideo /sos /NoSerialMice

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NoSerialMice Syntax
/NoSerialMice - Disables the detection of serial mice on all COM ports. /NoSerialMice:COMx - Disables the detection of serial mice on COM x, where x is the number of the port. /NoSerialMice:COMx,y,z - Disables the detection of serial mice on COM x, y and z. 

NOTE: The /NoSerialMice option is not case sensitive.