I believe what you are referring to is a simple extension to the remote shutter, utilized in a script to do more tasks than just a shutter press. It will not communicate with any existing Canon software, and you will not see the camera's viewfinder image or photos on the computer. There's a video that for convenience has movies of the PC screen (running a completely custom piece of software) and the camera's viewfinder overlaid, that may have confused you.
Try searching these forums for more info about that, I don't have the time to search it for you atm.