System Sensor BX-501 Plug-in Detector Base

System Sensor / Notiifier BX-501 Plug-in Detector Base is used with Notifier model CPX-551 ionization and SDX-551 photoelectronic smoke detector heads. The BX-501 base is intended for use in a 2-wire intelligent system, with screw terminals provided for power (+) and (-), and remote annunciator connections. Communication takes place over the power (+) and (-) lines. This detector base mounts directly to 3-1/2 inch and 4 inch octagon boxes, 4 inch square boxes (with or without plaster rings) and single gang boxes.