So, I really appreciate the response GRJ, but that schematic references the board that has three locations for external connection. My board, seen in the picture at the top of this post, has only two positions. The leoco style connector (2 pin) with the black and white wires attached (came with the board), are to go to the Fan. The three position screw-in terminal block has a label saying Pwr/Cam. along the edge of the block. The drawing you link is the same as the one I have from an earlier version of this board. I am thinking the "Pwr/Cam is referring to track power, but I am not sure, and the 'Cam" is referring to the magnetic sensing reed switch. This board came from ERR, in a package labeled Chuff/Puff. Since the notes I saw implied you can use this board if running Command Control only, I opted to not use the puffer board.