As long as the new outdoor sensor is one of the types supported by the ObserverIP, you can share the same outdoor AND indoor unit with both a display and the ObserverIP. For that matter, you can add multiple displays as well. The receiving end of the data is just an RF receiver and does NOT send signals BACK to the sensors arrays. I am currently using an WS-2902 with its color display along with a ObserverIP which feeds my Meteobridge (this will shortly be confirmed as the WS-1600-IP).