FYI: USB-Serial Port issues in Vista

[The Thing]

For all you who use USB - Serial Port adapters.
After an aftenoons research I have found that if you add the following environment variable to your system by doing:

Control Panel, System, Advanced tab, Environment Variables, New...

Type in :-

Variable name: DevMgr_Show_NonPresent_Devices
Variable Value: 1

When you then do:

Control Panel, Device Manager and select View menu, Show hidden devices

under Ports you will see all the USB-Serial Ports you ever have had assigned even though the adapter is not in place, you can then un-install all those pesky Com ports (I had 15!).

You then need to go down to Universal Serial Bus Controllers and delete all the phantom USB Serial Controllers

After that it's a lot easier to control the port numbers assigned by Vista in Device Manager.

Unfortunately you can't force a particular USB-Serial adapter to have the same port number every time it's inserted, it depends on which USB port you stick it in. According to Microsoft this is to prevent conflicts.

Using a hub or active extension or both complicates matters but labelling the sockets all the way through the chain then assigning the COM# you want for that adapter in Device Manager and then always connecting things the same way seems to work OK. So I have labelled my laptop USB ports and the adaptors so they always go in the same socket and then get the same number.

I hope this helps someone when they are trying (Vista is very trying) to get imaging!

Dunc

BTW there are some registry keys you can use to control the number of port # that can be assigned but they are not for the faint hearted.

[Carole]

I hope it is OK to post on this thread.
I have followed the above instructions as I want to attach the serial adapter which controls EQmod and so far have been unable to do so because it wants to be assigned to Com20 and EQmod only gives an option up to Com16, therefore this has been my stumbling block.

This is the selection of Com ports I have assigned and since I don;t want to muck anything up, I wonder whether you could tell me which ones I should delete (or all of them, and if so will anything assigned to those ports currently find new ones once plugged in)?  

i.e. is it the ones labelled:
Prolific USB to serial comm port (Com 20 is one of those)
USB serial CH etc
ZTE Diagnostics

Or do I delete all of them and is it just a question of highlighting them and pressing delete.
Sorry, I don't normally tamper with the inner workings of the PC so don't know what I am doing.

[Mac]

personally I would do the following. (exactly the same way as Duncan has done)

1) get all your driver disks for the devices you use, and the usb to serial adaptor BEFORE YOU START.

2) delete every port listed. (leave number 1 to the end as it will probably be the mouse)(if the mouse does stop working, unplug it and then replug it in, make a note of the port number allocated and then delete that last.)

3) get a marker pen and some masking tape.

4) once you have deleted every port, plug the mouse in to its normal socket, this will allocate the first usb socket and com port.

5) for each device you use, plug one in, into the port you always use, make a note of the port number it has allocated and what usb socket you have plugged it into, (i normally start with  looking at the laptop, front right usb socket 1, next one round 2, ect, this will normally give me 6 usb sockets, 4 normal and 2 USB2 )

6) Dont forget that the usb socket and the com port number are two totally different things. (the usb socket can be allocated any com port number)
Once you have finished you should have all of your devices plugged in and allocated their new com port number.
which you would have made a note of on the masking tape that you have stuck round their leads, listing, device, usb socket position and com port.

7) once you have done that , unplug everything, reboot, plug everything in one by one again, and see if the com ports have changed. They shouldn't have, and that hopefully should be the end of your troubles . or the start of even more .

Hopefully this will make sense.

Mac

[Carole]

That does make sense Mac.  These days I always plug hardware into the same USB port, but I guess all these com port numbers arose from some time ago when I had a number of bits of hardware (which I now no longer have) and USB hubs and did not know at that time to be consistent.

So it is OK then to delete all the ports named as follows?
Prolific USB to serial comm port (Com 20 is one of those)
USB serial CH etc
ZTE Diagnostics

Carole

[Mike]

Just delete all of them Carole then you can start to replug items back in and reinstall drivers as necessary.

[Carole]

Thanks Mac and Mike.
Highlight and delete I assume.

Carole