I may have figured out the answer to my problem on the way home from the job site, but I won't be back for a few days to trouble shoot it. I am having a problem with Output 2 not turning off. Output 2 is set to voltage since it is connected to a siren. I am showing a near constant 13 volts from the positive side of Output 2 to the common negative terminals. I joined all my negative wires together for all my zones, sirens, strobes, etc. I am connecting the minus side of the siren wire to the common negative terminal. I think that is my problem. The minus siren wire must go to the minus siren terminal. It appears that the M1 is switching the negative side of the siren output. Can someone with an M1 on the bench confirm that? Or, Spanky, is my deduction correct? As soon as I fire up the panel, Output 2 puts out 13 volts and sets off my siren, disarming the system does nothing. Since I have the negative side of the siren wired to the common negative of the panel it is constantly on and I can't turn it off. The panel itself does not go into alarm but there is a voltage present. I didn't measure the voltage from the plus side to the minus side of the siren output because I didn't think of it until I was in the truck home. TIA.