It's virtual so you don't need any extender at all. The plugin handles it for you. HS Light status would be possible but then we would be forced to simulate the Lutron RadioRA protocol instead. I haven't looked at that yet so I don't known how hard it would be to add.
General 2 way communication through the RS232 protocol is still not possible.
Creator of the TSU9600 Homeseer plugin & Plane9 a 3d Music visualizer that can be found at http://www.plane9.com
