Anyone have a working USB-Serial adapter?

Discussion in 'Parallels Desktop for Mac' started by rcomeau, Aug 9, 2006.

  1. rcomeau



    This subject gets mentioned from time to time in other threads, but I'd like to start one specific to this one issue...

    The main reason I purchased Parallels was to communicate with a piece of lab equipment using software running under Windows. I also use the device using some home-grown Mac software via a KeySpan USB-Serial adapter (USA19HS), which has been working for years.

    I have had only limited success with Parallels and the latest beta is no different. Here is what I am doing. If anyone else has gotten further that I, please be good enough to share it with us here!

    1: Before launching Parallels, I plug in the adapter.
    2: From the terminal, I type "sudo kextunload /System/Library/Extensions/KeyspanUSAdriver.kext" to unload the Mac-side driver to prevent the "USB device in use" blah blah message.
    3: I launch Parallels, and connect ti the USB device (I dont have autoconnect on). Sometimes, I get a kernel panic here and have to reboot the computer. Other times I get a few iterations of the device connect/disconnect/connect/disconnect/connect chimes, it usually settles down to connecting.
    4: I launch the KeySpan Serial Assistant software and it recognises the device.
    5: Click on the diagnostic pane and test the port, and it always fails.

    If I use the device without changing speeds, I can talk to a Garmin eTrex Legend via serial port ONCE, that is, I can send or receive data once, then the serial port stops working and I have to unplug/plug the adapter back in agan. It does not work at all with the lab equipment, presumably becuase the software tries to configure the port.

    So can anyone who has a working USB-Serial adapter please chime in with some tips. I have looked at the SerialClient software option a while ago, but at the time I checked, it did not support changes in the port speed on the fly (that is, the software talking to the serial device changing the speed).

    Thanks for any info.


  2. pilif



    I'm using a Usb-2-Serial adapter with a chipset by Prolific and I have no problems what so ever, even in the release version of Parallels and that even though I have installed a driver for it on the mac too.

    What I did was to disable USB AutoConnect in the parallels configuration. Now whenever I use the adaptor from within parallels, I use the devices/USB menu to manually connect the adaptor.

    Works perfectly.


    I have the same adapter and don't have any trouble with it at all. I DONT unload the kernal extension though, the mac knows it's there. When I connect it via the usb menu in parallels, windows chimes once and sees it. Then I can use it within windows with no trouble. I've used it for ham radio control, and to palm sync an old smartphone.

    Works fine.

    Not my extra usb audio adapter though, parallels complains that it's in use consistantly....
  4. frankieg


  5. powell


    Keyspan Working

    I got my Keyspan 19QW serial adapter to work in the Beta (finally!!!). I did not install the mac driver for it. I installed the Windows driver for it from Keyspan. I select auto-connect for the USB options in Parallels.

    Went into the Windows VM, plugged in the adapter, and voila! Windows recognized it, and the Keyspan Assistant showed it listed allowing me to assign it a COM port, etc.

    I'm very happy I got it working. I'll try it out on some real serial connections this evening.
  6. powell



    Well, I spoke to soon. I got the device working; however, it cannot maintain a decent serial connection. The COM port frequently freezes, the USB loses "sight" of the serial adapter, etc.

    I might have to try out one of the serial ports listed above.
  7. amahler



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