CrossRoads:
Why not write a sketch that receives characters from the serial monitor and acts on them?
You have to press enter for serial monitor to send them out.
That's pretty simple to implement.
I would be interested in this as an approach. I could see how that could work in code but I am unsure if the USB slave device. Would most likely need to scope it out. I am new to Arduino and an looking at a project with two arduino communicating over ether wifi or FM signal. One ardiuno with a USB touch pad and sending data between the two using something like this link EasyTransfer Arduino Library « The Mind of Bill Porter
My end result would be the target arduino would be taking commands from the primary arduino with attached hardwired USB.
Any thoughts?