Preventing PnP discovery on com port

We have an 'intelligent' UPS attached to our device on a serial port but
we're not using the application or driver. Each time we boot the 'found new
hardware' wizard comes up for that device. Is there any registry setting or
something we can change to eliminate the discovery but just on that one
serial port? Thanks!

"LarryW" <lwdaddio@newsgroups.nospam> wrote in message
news:VA.000000b1.00e33e7f@newsgroups.nospam...
> We have an 'intelligent' UPS attached to our device on a serial port
> but
> we're not using the application or driver. Each time we boot the
> 'found new
> hardware' wizard comes up for that device. Is there any registry
> setting or
> something we can change to eliminate the discovery but just on that
> one
> serial port? Thanks!

Set the following in the registry:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\A CPI\PNP0501\1\Device
Parameters]
"SkipEnumerations"=dword:ffffffff

The above is for port 1, for port 2 use ...\2\Device Parameters

Google skipenumerations for more info if desired / needed.

You might also need to add /fastdetect to BOOT.INI similar to this:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOW S
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micro soft Windows XP
Professional" /noexecute=optin /fastdetect /bootlogo /noguiboot

That will affect all ports though, and I'm not sure if it will be needed
or not.

Hope this helps,

Dave

In article <e0Fwmiv1IHA.3884@TK2MSFTNGP05.phx.gbl>, Dave R. wrote:
> From: "Dave R." <dwragle (at) drbsystems (dot) com>
> Subject: Re: Preventing PnP discovery on com port
> Date: Wed, 25 Jun 2008 15:21:17 -0400
> Newsgroups: microsoft.public.windowsxp.embedded
>
> "LarryW" <lwdaddio@newsgroups.nospam> wrote in message
> news:VA.000000b1.00e33e7f@newsgroups.nospam...
> > We have an 'intelligent' UPS attached to our device on a serial port
> > but
> > we're not using the application or driver. Each time we boot the
> > 'found new
> > hardware' wizard comes up for that device. Is there any registry
> > setting or
> > something we can change to eliminate the discovery but just on that
> > one
> > serial port? Thanks!
>
> Set the following in the registry:
>
> [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\A CPI\PNP0501\1\Device
> Parameters]
> "SkipEnumerations"=dword:ffffffff
>
> The above is for port 1, for port 2 use ...\2\Device Parameters
>
> Google skipenumerations for more info if desired / needed.
>
> You might also need to add /fastdetect to BOOT.INI similar to this:
>
> [boot loader]
> timeout=30
> default=multi(0)disk(0)rdisk(0)partition(1)\WINDOW S
> [operating systems]
> multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micro soft Windows XP
> Professional" /noexecute=optin /fastdetect /bootlogo /noguiboot
>
> That will affect all ports though, and I'm not sure if it will be needed
> or not.
>
> Hope this helps,
>
> Dave
>

You got me started down what looked like the right path but the COM1 and COM2
ports don't seem to be ACPI and were in the 'Root' instead. And the entry
wasn't the port number '1' but was 'PnPBIOS_12'. When I set that key's
SkipEnumerations value then I stopped getting the 'new hardware found'.
Unfortunately, now the port isn't even seen so I can't use COM1:.

When the new hardware wizard would come up, if I went to the next screen of
the dialog there was a check-mark to say not to ask me again and if I checked
that then I didn't see it on subsequent boots but was still able to use the
COM port. What I need is to be able to set whatever it is that checkbox does
in my target design file.

The registry entry I ended up using was:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\R oot\*PNP0501\PnPBIOS_12\Dev
ice Parameters\SkipEnumerations