I need to set up a simple alarm system. I only need three door-contact switches, that will trigger an alarm upstairs when the doors are opened. The On/Off switch should be upstairs, along with the actual alarm. I don't need motion detectors, auto-dial, cell-phone backup, etc. Basically, I need a glorified door-bell. Can anyone point me to a website that deals in such things, or recommend a product that can do this? THANKS!