HM-613PC-2, HM-613PC-4 are photoelectric smoke detectors available in 2-wire and 4-wire models. It's a conventional detector and doesn't take an address on SLC.  Leveraging the principle of smoke particles reflecting infrared light, its smoke chamber enables precise detection of early-stage fire smoke, ensuring timely warnings. During an alarm event, HM-613PC-2, HM-613PC-4 will go into alarm when signal level exceeds the alarm threshold and send the alarm signal to the control panel and the LED indicator remains constantly illuminated to provide clear visual alerts.