I do own one.
It is a serial port connection to the PC for the touchscreen.
It needs to have the drivers installed to make it work.
I can only tell you how the windows drivers work since that is what I am currently using. Moving your finger on the screen is like moving your mouse and tapping(or putting your finger ther and holding) it works as the left mouse button but it has a little program that run in the system tray that can switch it between left mouse and right mousebuttons for the tap.
I am currently at work and do not have my drivers CD with me but IIRC it did have a linux directory on it.
ohh and here you go rammic something for your head