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Walking on the Moon


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For starters label them up and always plug them in the same USB ports.

you can change the Comport number in Device manager...

Is you keep juggling the adaptors between different usb ports you can end up running outside the usable com port numbers very quickly...even the though the OS can use stupid comm port numbers most software wants lower numbered ones - especially older software...

Every time you plug a usb device into a different port or onto the end of an active extension lead or hub etc it creates a new instance of the device which is what can lead to the confusion.

If you look in device manager you will only normally see active devices - ones actually connected at the time there are a couple of command line switches that allow you to see all instances of the devices and have a clear out...

this text comes from here


its about com ports but the same technique can be used for any "device" category at one point I think I had 11 instnces of a Meade DSI and similar for my SPC900 as i had been moving them around ports on a hub and the hub around different ports on the laptop...

1. Click Start, point to All Programs, point to Accessories, and then click Command Prompt.

2. At a command prompt, type the following command , and then press ENTER:

set devmgr_show_nonpresent_devices=1

3. Type the following command at command prompt, and then press ENTER:

start devmgmt.msc

4. Click View > Show hidden devices. This will display devices that are not connected to your computer but Windows XP still reserves space for them.

5. expand the section that the device your having problems with is in.

6. remove the instances of the device...

Reconnect devices... and hopefully everything should be ok...

I know have all the ports labelled so I connect the same usb devices to the same place every time.


This should really be a sticky....

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If you don't want to do a clear out but have a high com port number such as 14 which your software wont recognize you can reset the number from device manager, open up the com port in question and under advanced change the number to a lower one. It will show all these as being in use but the aren't (just make sure they aren't actually being used by another of your devices). It will give you a dire warning but just click ok and you should be up and running,

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