The Sync Circuit module synchronizes SpectrAlert Advance strobes at 1 Hz and horns and chimes at temporal 3 over a single pair of wires. Patented module technology also allows the silencing of horns or chimes on horn/ strobe and chime/ strobe models over a pair of wires. The MDL3 Module is designed to work with the SpectrAlert and SpectrAlert Advance series of notification appliances to provide a means of synchronizing the temporal coded horns and chimes, synchronizing the one second flash timing of the strobe, and silencing the horns and chimes of the horn/ strobe and chime/ strobes combination over a two wire circuit while leaving the strobes active.