Memory serving correct the middle would be your output and the two sides would be your switch able inputs. If this is not the case try the other 5 choices. A 9v battery and xmas light usually make good test devices. By any chance did you see any video wires in that bundle? I'm trying to take this a step further and make a switch able line for not only sound, but also video. No room for extra monitors in this thing so I gotta use what's there.