Use the D278S Four wire Addressable Detector Base with smoke and heat detector heads to provide early warning fire detection for life safety and property protection systems. The detector base is a 12 VDC base for use in systems controlled by a D7412G or D9412G 12 VDC Control Panels with a D8125 POPEX Module. The detector base has a built in POPIT to provide individual addresses on the FACP data expansion circuit. The detector base accepts the D285/D285TH Photoelectric Smoke Detector Heads, the D286 Ionization Smoke Detector Head, and the D603, D604, and D605 Heat Detector Heads. When used with the D285 detector heads, the detector base indicates Chamber Check trouble to the control panel through the POPIT bus. The Chamber Check trouble indication appears on the keypads as a fire trouble.