kdb215: COM Port Number Mapping in Windows95

Title: COM Port Number Mapping in Windows95
Keywords: COM Port Number Mapping in Windows95
Date: January 13, 2006
KDB: KDB-215
Revision: 0.01
Author: AES
Distribution: External

Introduction:

Windows95 installs most of our devices at COM5. In some cases it is desirable to have our devices located at different COM numbers such as COM3. The following text describes how to do this by modifying the registry. Please note that is a kludge and it is really recommended that you just use applications that can handle any COM number rather than use this method.

Warning!

The following method requires you edit your registry. There are always some risks when accessing the registry directly. Failure to follow the directions exactly as follows might result in erratic operation of your Windows95 machine.

Instructions:

The following example shows how to move a port from COM5 to COM3. Some parameters may vary depending on your setup.

1. Check your system using via the Control Panel, system properties page to get a picture of the COM numbers currently being used on your system.
2. Click on the Start button and select RUN. Type in “regedit” and hit Enter.
3. Using your mouse select the following branch of the registry:
   My Computer\HKEY_LOCAL_MACHINE\Enum\MF\Child0000
   Child0000 is used for the first device on a particular board, Child0001 is used for the second etc.
4. For DFlex boards you would then select:
   ROOT&MULTIFUNCTION&0000
   for Blue Heat boards you would then select:
   PCI&VEN_11B0&DEV_000?&BUS_00&DEV_11&FUNC_00 (where ? can vary depending on the type of Blue Heat board)
5. The only parameter you need to change in here is the “PORTNAME”. In this example it is “COM5” and we will double click on it and change it to “COM3”. I would however recommend you use essentially the same method to change the references to “COM5” in the “DeviceDesc” and “FRIENDLYNAME” sections for completeness so that they match the name used in “PORTNAME”.
6. Repeat steps 3 to 5 for any other ports you wish to move.
7. Exit Regedit. You should find that the names are immediately, but it might be best to reboot to ensure the new parameters are in sync with all applications.

End of KDB-215