The main two-way audio satellite ATS1521N is an audio device that is used for the verification of audio alarms. Depending on the variant of the control panel and the firmware, up to 32 ATS1521N satellites may be installed in protected facilities and connected to an Advisor Advanced panel with the bidirectional audio module Accurate ATS1520 modules and the ATS7700 PSTN module. The ATS1521N allows you to connect up to 3 ATS1522N slave audio satellites. Any mixture of a maximum of four ATS1521N and ATS1522N is allowed on the communication bus. Minimum sound level at 10 meters distance: 55dB. Dimensions: 157x91x34mm. Temperature: -10 to 55ºC.