PC question on COM ports & USB grief

[S2central.net]

For the comm savvy IT folk... Question and picture in attached PDF.

I have a USB - serial adpater that works great with VAGCOM on the S2. But it only works when plugged into one USB port (out of three) and only when I assign it COM3 - nothing else in the range is available and I can't see a way to release the other assignments. They seem to be stuck in the registry - but I'll never find them without help from an expert.

[mcandmar]

Try booting into safe mode (keep hitting F8 before the machine boots), then look in device manager and remove any com ports listed.

[S2central.net]

I'm always a bit afraid of 'safe mode'...

After I do this, will I be able to reboot normally into the 'unsafe mode' what I'm using now ?

I feel a lil backup coming on

[GazzaG60]

some of the usb to com devices have assigned com in the converter.

is it not USB2. it may only be usb 1 compliant and the software port assignment may not function if an incorrect call is made.

i got this issue too. older laptops have a serial port. the new dell ones dont and as an it manager it makes it difficult for my engineers and me.

i just got my old laptop back as vems can be funny with the converters. in fact so can linkecu and a few others.

[mark_s2]

Paul,

Check your BIOS for the hardware IRQ assignment for COM 1 & 2 - you can usually disable if you do not use the hardware port.

Also do you run programs such as MS Active sync that if enabled can will tie up a COM port assignment.

[S2central.net]

I do use COM1 whilst docked - for the GTech.

Just been in and out of SAFE mode... I can't see how to disable the COM ports... The only devices that present themselves are LPT1 and COM1...

Its only when you go to advanced settings for COM1 that you see the list of all available/unavailable COM ports that can be assigned to the device.

Hadn't thought of BIOS right enough - suspect all I have there is a hook for COM1 activation (and LPT1 of course)...

[Jamo]

Sounds like the usb driver is bound to a specific port, I have had this with the ecutool lead but it was easy to correct in this case as you just had to install the driver when prompted.

No amount of booting etc will work as it's the driver doing this.

[mcandmar]

Forgot to mention, select "show hidden devices" from the view menu. That should show you all devices that have been installed but are no longer connected.

Com1 and Com3 share the same IRQ, and so do Com2 and Com4. If you have a com port its usually Port1, if you laptop has a built in modem of iR port they will grab a Com port too. You can usually jiggle them around in the bios, or disable them if you dont need them.

[S2central.net]

Still no dice mcandmar --- that option did display a lot of 'non plug and play' devices but didn't expose anything new in COM or LPT ports. I hate PCs - short for Piece of Crap really...

[Nuvo]

Run regedit and find this entry :HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contr ol\COM Name Arbiter

Click on the ComDB binary string entry. Copy and paste its value on here please.

[S2central.net]

I only wish I knew what it meant... I can't cut and paste for some reason but here it is -

FF 07 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00

Cheers for any insight Nuvo...

[Nuvo]

One more question for the moment. Does your lappy only have one physical serial port with the rest being virtual ports?

[S2central.net]

Oh yes indeed...

And the physical port is on my dock station - the lappy itself only sports USB connectors.

[S2central.net]

PS - that registry entry was whilst sitting docked here... No COM ports in use (if that matters)

[Nuvo]

Highlight the ComDB key in the registry and then right click and select Modify Binary Data from the context menu.
Overwrite the first two bytes FF 07 with the values 01 00. Remember to delete the extra two 00 bytes from the end of the binary string.

Now go back into Device manager and select the advanced ports settings. You should now have a clean slate with COM Port 1 being the only port that is in use.

You might be able to assign the COM ports now from this state, although I suspect you might need to faff with the USB-Serial adpater device driver registry or .ini settings (delete as appropriate) to get what you need.