The Keyspan adapters are known to work well with non-Windows environments. I then tested the adapter in my windows app and indeed, the serial connection is working! I am using Windows XP Pro as my guest OS, so, unless you are set up the same, the exact steps may differ somewhat. Windows now seems just fine with the COM3 I created - there's no yellow '!' in device manager, and the Keyspan adapter LED is solid green. Restart Windows XP, and while it's coming up, go ahead and click Conncect in SerialClient.Baud Rade is 115200 and defaults on the rest. Make the stream path /tmp/serial, just as above. Now, finally, run the SerialClient software downloaded above.Finally, put a checkmark in the box labeled Create Pipe, and enter path of /tmp/serial without the quotes. After enabling Port 1, I set the Port Number drop-down to User-defined, and set it to IRQ 4, 3F8 as above. In VirtualBox, I then edited Serial Ports in the Settings area of my virtual machine.The device was created, but for some reason, it ended up being a COM3, IRQ4, at address 3F8 (this is important in a moment). Basically, I wanted to force XP to set up an item in Device Manager for a COM port. In XP, I went into the Add Hardware wizard, and scrolled down to the bottom to add hardware I pick from a list.Downloaded SerialClient, the excellent app that seems to make this work.

Installed the Keyspan drivers on my Mac (Leopard, 10.5.4).It turns out that I hadn't turned them on in VirtualBox, so I did that. Windows XP installed without a hitch, but it had no COM ports set up.Here's what I did just now to get my Keyspan USA-19HS USB-to-Serial adapter working in VirtualBox under Windows XP: For some of us, we not only need to run a Windows app, but that app requires a connection to a serial device. Sun's VirtualBox is a slick new virtualization alternative to VMWare Fusion, Parallels, and the like.

Keyspan 19hs usb 2 serial xp driver