Hello Brian -- I seem to be having some of the same problems I see reported here - one siren out of 6 total that will not sound; window and door sensors that install just fine, and then suddenly indicate "problem" or "window/door open" or "low battery". Changing batteries does no good, and the indicated door or window is never open. I've installed new sensors only to have the same problems. I've got the SC1200 now, but did have the DS700 -- exchanged due to its limitations. I had experienced having to take out the batteries and unplug to correct any sensor problems. Now this morning I have a new "problem", I accidentally triggered the alarm, and now the console horn makes a much different sound than it did previously. Any help from anyone would be greatly appreciated. JudyH