The SPS1 is the Smart way to connect two receivers to one LNB When the receiver connected to the priority port it switched on. it take full control of the LNB determining polarity and tone When the priority receiver it turned off, the second receiver has full control of the LNB If the main receiver continuously powers the LNB when twitched off, the SPS1 can he controlled by the TV/SAT button on the remote control by connecting the flying lead to pin B on the TV Scart socket or any other O/12V accessories output