This advantage-set contains everything that you need for a fire-alarm system. The radio smoke-detection station as well as 3x radio modules FRM 320 (75 17 68) and RM 420 (75 18 07). In case of an alarm from the smoke detector a radio signal is sent to the station, which triggers an alarm. Similarly, all the other smoke detectors are activated. In addition, the activated smoke detector is shown through the signal indicator. A switch contact (changer) is available at the alarm centre or at a telephone dialler for forwarding the alarm.