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How to delete virtual COM port numbers assigned before

OSR_Community_UserOSR_Community_User Member Posts: 110,217
Hi all

I have a problem with virtual COM port . System has assigned COM port no.s
and I am not able to unregister them properly . Can anybody suggest me a way
clean up the registry ?

Thanks,
srinivasa


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Comments

  • OSR_Community_UserOSR_Community_User Member Posts: 110,217
    ** Reply to message from Srinivasa Rao Deevi on
    Wed, 20 Feb 2002 08:57:52 -0800


    > I have a problem with virtual COM port . System has assigned COM port no.s
    > and I am not able to unregister them properly . Can anybody suggest me a way
    > clean up the registry ?

    If you are on Windows 2000, you can directly edit the "COM name database" in
    the registry. Completely undocumented, but I've done this myself many times ---
    on my driver test computer.

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter

    The "COMDB" value is a binary field that seems to be a bitmap of installed
    ports. If you have COM1 and COM2, the first byte will be 0x03. Add COM3, 4, 5,
    and 6, and the first byte will be 0x3F. Go up to COM8 and you'll see 0xFF,
    0x01. And so on.

    Be careful not to change the length of the string of bytes when you edit it.
    I have no idea what will happen if you change the length.

    Sincerely,

    Chris Myers
    Senior Project Engineer
    Quatech, Inc.


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