Forgive my newbie question. I am trying to create a 'Dry contact' that will set a bell off on a QSM-624ET Public Address Amplifer. I have heard a relay must be used to do this, I have a srd-05vdc-sl-c wired up with pin8 to the S and 5V to + and GND to GND, the COM is suppose to be the middle output pin and the trigger the last output pin. May question is, is there actual voltage that is passed over these lines? I've connected up an LED and nothing comes out so it this achieving what im after?