Using an internal modem with Virtual PC / Virtual Server

Using an internal modem with Virtual PC / Virtual Server

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Anyone who has used Virtual PC / Virtual Server for a while will have got their head around the fact that you cannot access physical hardware directly from the virtual machine - with the exception of devices connected to a serial or parallel port.  Well, as a number of people have discovered there is an interesting exception for 'internal modems'.  These are modems that are usually on a PCI card in the physical computer - or on a PCMCIA card in a laptop.

The trick here as that internal modems almost always implement a hidden serial port - to which the modem is hardwired.  This is true even of WinModems.

As such - all you need to do is to figure out which COM port is used by the internal modem (poking around under Device Manager will usually get you the answer quickly) and map that to COM1 in the virtual machine.  You can then just use a 'generic modem' configuration in the virtual machine to get this to work.


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  • Sadly, this doesn't work for the software modem used by the MP-900 Microsoft phone.  I loved that phone, but I have never been able to get the dang thing to work with Virtual PC (and sadly, the PC that did run win95 with it has passed on)

    Say Ben, if you get the chance & know someone that has one of the 900 Mhz microsoft phones & see if you can't find out why it doesn't work with Virtual PC.

  • ya know what, never mind. The wife informs me that she snuck the phone to the local electronics recycler to me a few months ago.

    Dang.  I loved that phone.

  • You can never trust wives with hardware :-)

  • I've never seen a hidden serial port with a PCI modem or WinModem.  I've only seen them with ISA modems.  The reason a PCMCIA modem gets one is that PCMCIA also provides an ISA-like interface.  Cardbus provides a PCI-like interface.

  • My laptop has an "Agere Systems AC'97 Modem", which I believe is a modern incarnation of the Lucent WinModem. If you look in its device manager properties, Modem tab, it says "Port: COM4". I can connect to it in HyperTerminal using "COM4" - ATH returns "OK".

    My "Nokia Bluetooth Modem" has Port: COM0 though, maybe because it's not connected right now.

    At a past project, I had an 8-modem PCI card, and it did create 8 additional COM ports. Together with the 2 real ports, 1 other PCI modem and 2 USB modems, I ended up with COM13. Of course, next door was the guy with the 128-com port card...

  • Connectix had serial and parallel capability with VirtualPC eons ago.  What have you done for us lately?  :)

  • Vista host support?  Hardware virtualization support?  64-bit host support? :-)

  • Yes, I have used WinModems like that in the past, PCI, Connexant & Lucent ISTR.

    The most common problem then is that Windowes recognises the modem using PnP & tries to install the drivers for the WInModem hardware interface - which isn't virtualised & will not work.

    The trick is to either use a Standard Modem driver & enter ones own AT string, or else choose the driver for another modem which has a similar AT command string.  That was fairly simple for the Connexants where the AT command set is similar or identical - a bit more difficult for the Lucent.  I also remember getting a USRobotics WinModem to work- the trick there was just to choose a modem driver from the right code base Courier/Sportster, with their different S-Register sets.

  • Hi,

    I need a help for COM port configuration on HyperV.

    My system uses two COM ports for GSM modem, one other hardware.

    Now, issue is I have an internal PCI modem for voice calling, I am not able to assign this to my VM.

    As mentioned above, modem uses COM3. problem is, in VM configuration, it don't give me option to add a serial COM port.

    Is this a limitation with HyperV?

  • Anonymous -

    Hyper-V does not allow you to connect a physical COM port to a virtual machine.



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