What is windoes doing?

dwight dkelvey at hotmail.com
Tue Nov 20 17:21:40 CST 2018

Great Todd. That is just what I'm looking for. It makes sense that it would keep track. I have two different ftdi chips that I'm using so I can see how it got messed up.

From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Todd Goodman via cctalk <cctalk at classiccmp.org>
Sent: Tuesday, November 20, 2018 5:43 AM
To: cctalk at classiccmp.org
Subject: Re: What is windoes doing?

On 11/19/2018 11:34 AM, dwight via cctalk wrote:
> I have a question. I use the USB port for serial. In my program, I use a fixed com port. When going to the control panel, I find that I see (in use) tags on some of the com ports. I'm the only one currently using the com ports but recently another (in use) showed up, requiring me to modify my program to use another com port. How does one unuse a com port? how do I find out what is using it so I can stop it? I'm using windows 7 professional. Has anyone else had this problem?
> Dwight
Windows "remembers" com ports of USB devices based on the VID/PID of the
USB device.

This allows the same device (USB com port) to get the same COM
assignment but means you end up with a ton of useless COM port
reservations when you're using a large number of different USB COM devices.

Something like
has instructions for removing them in Windows 7.

I could have sworn I just uninstalled them from Device Manager but I
forget now as it was a while ago.


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