Symptom:
After replacing or installing a new Digi board in Windows 2000, the com ports are not being reused, but now are starting at a much higher number. How do I fix this?
Solution:
This is a known issue in Windows 2000. The related Microsoft article is: Q271523.
To resolve phantom com ports, you will need to hack out the COM port numbers using the following procedure:
1. Open Start>Settings>Control Panel>Add New Hardware. Double-click Add New Hardware.
![](http://ftp1.digi.com/support/images/click_add_new_hardware.gif)
2. Click Next.
![](http://ftp1.digi.com/support/images/click_next.gif)
3. Select the Uninstall/Unplug a device radio button. Click Next.
![](http://ftp1.digi.com/support/images/select_uninstall.gif)
4. Select the Uninstall a device radio button. Click Next.
![](http://ftp1.digi.com/support/images/uninstall_device.gif)
5. Select the Show hidden devices check box. Select any Digi Adapter that is present. Click Next. Repeat steps 1-7 until all Digi adapters (or ports) have been removed.
![](http://ftp1.digi.com/support/images/select_digi.gif)
6. Select the Yes, I want to uninstall this device radio button. Click Next.
![](http://ftp1.digi.com/support/images/select_yes.gif)
7. Click Finish.
![](http://ftp1.digi.com/support/images/click_finish.gif)
**Digi recommends you back up your registry before doing any editing. Caution: Careless editing in the Registry may have disastrous results and could require a complete reinstall of the WINDOWS NT operating system. Digi assumes no responsibility for any problems ensuing from improper editing of the registry.**
8. Open Start>Run. Type regedit. Click Ok.
![](http://ftp1.digi.com/support/images/regedit.gif)
9. Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter. There should be a value called ComDB, Type REG_BINARY in this key. If you have phantom ports, it should look somewhat like below with "ff ff ff ff ff...03" for the data. Double click on ComDB.
![](http://ftp1.digi.com/support/images/comdb.gif)
10. You will need to delete the ffs and leave the 03 at the beginning.
Before editing:
![](http://ftp1.digi.com/support/images/edit_binary.gif)
After editing:
![](http://ftp1.digi.com/support/images/done.gif)
11. Reboot the machine and you should be able to use the comports that were lost.
Last updated:
Jan 09, 2024