WinXP BSOD on MODEM Probe with USB2Serial

Have a funny one here...

We need to support some old WindowsXP specific Applications that need to use a MODEM to communicate with remote embedded hardware. We're running the VirtualHere Server on Ubuntu 64bit with a Prolific USB to Serial Adapter with a Serial MODEM attached to that. Ubuntu dmesg output lists the Prolific USB to Serial Adapter as a pl2303 device.

Opening the Prolific USB to Serial Device via the VirtualHere USB Hub results in an instant BlueScreenOfDeath on the WindowsXP PC.

On further diagnosis, we found that removing the MODEM and opening the Prolific USB to Serial Device, via the Virtual USB Hub, does not cause a BSOD on the PC. Just to make things more interesting, attaching the MODEM, after the Prolific USB to Serial is in use, does not cause a BSOD either and the MODEM is perfectly usable... go figure.

Looks like the Windows XP machine has a panic trying to probe for devices beyond the Prolific USB to Serial Adapter.

As a checkpoint, we moved the Prolific USB to Serial Adapter and MODEM directly on the Windows XP PC and no issues were encountered.

Any insights will be much appreciated.
We're going to attempt the same test with a FTDI based USB to Serial Adapter next.


Hi, I have heard of this issue before, could you send me the c:\windows\memory.dmp when xp crashes to mail [at]


Thanks for the reply. I'll see if the memory.dmp file is still available and send it along.
Just a update, we swapped the cable for one based on a FTDI controller and had no further issues. Tried two different FTDI based cables, one used the latest FTDI drivers from and the other had a Vendor supplied driver (the USB vendor ID was set to their brand).