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Hyper-V locks up PCI modem port on host machine RRS feed

  • Question

  • I have a Windows 2008 Server with a PCI US Robotics Fax/Modem card installed.  Additionally, this Win2008 Server is running a virtual machine (Hyper-V) that is configured to be an SQL server.

    When the virtual machine is OFF.  I have no issues with the Fax/Modem on the host.

    As soon as I start the VM, I cannot query my modem and all Fax/Modem functions stop working.  The issue is the COM3 Port assigned to the Fax/Modem is being opened and never released by the VM.  As soon as I stop the VM, all Fax/Modem functionality returns to normal and I can open COM3 and query the modem.

    Thanks, Jim

    Tuesday, April 21, 2015 10:23 PM

All replies

  • I installed a USB Modem (Creative Modem Blaster).  This has the same issue; actually both modems have the same issue (I left the internal US Robotics modem installed).

    Not all VMs are stealing my modems.  I have a Server with about 5 VMs and none of the VM's are stealing my modem.  I installed another VM that is being used as a domain controller and this VM does not steal my modem.  BUT, this one VM is stealing any modem I connect except a modem connected to the serial port.

    The VM in question is running SQL server under a cluster with 2 nodes.  It is using 3 of the 4 NICs, 4 CPUs and 8GM of RAM.

    Does anyone know of any reason a VM would grab a hold of a modem and not let it go?

    Friday, April 24, 2015 11:42 PM