Ralph,
I think I may have just succeed where others have been failing with USB-to-Serial.
I have been trying a bunch of experiments to get my URC MX-850 editor to work (that's a Universal Remote Control brand universal remote control). The editor for the remote only runs in Windows, and uses a serial cable to program the remote. I LOVE the remote, but despise the lack of USB support (not to mention it's windows-only).
AHEM,
Here's what I did just now to get my Keyspan USA-19HS working in Virtual Box:
I am using XP Pro as my guest OS, so, unless you are setup the same, YMMV.
1. XP installed without a hitch, but it has no COM ports. Ok, fine. I hadn't turned them on in VB.
2. Installed the Keyspan drivers on my mac (Leopard, 10.5.4).
3. Downloaded
SerialClient, the excellent app that seems to make this work.
4. Attached the Keyspan adapter.
5. In XP, went into ADD HARDWARE wizard and scrolled down to the bottom to add hardware I pick from a list. Basically, I wanted to force XP to setup an item in Device Manager for a COM port. The device was created, but for some reason, it ended up being a COM3, IRQ4, at address 3F8. (this is important in a moment)
6. Went into VB and edited Serial Ports. Picked Port0. For Port Number, I picked user-defined, and set it to IRQ 4, 3F8 as above. Port Mode is HOST PIPE, put a checkmark in the box Create Pipe, and enter path of "/tmp/serial" without the quotes. Ok to exit.
7. Now, finally, run the SerialClient software downloaded in #3 above. Make the stream path /tmp/serial just like #6 above. Select your serialport KeySerial1. Baud Rade is 115200 and defaults on the rest.
8. Restart XP and while it's coming up, go ahead and click CONNECT in SerailClient.
Windows now seems just fine with the COM3 I created. No yellow "!" in device manager. The Keyspan adapter LED is solid green.
Next, in XP, I headed into my remote control editor program and tried to talk to my remote via the USB-Serial cable. WOOHOO! It's working!
I know this is confusing, but I hope it helps. Good luck!