The standard system controller interfaces controls up to 5-off disabled refuge EVC outstations. Outstations are star wired to the controllers using 2 pair cable. Controllers are looped together with the master station over 3 pair cable. The combination of loop and star cabling enables installers to match system cabling to building layouts. The standard system controller allows adjustment of slave outstation microphone and speaker level. The standard system controller will test the audio path to all slave outstations. Testing is triggered externally e.g. by BMS or timer. Faults are reported at the master station and there is a fault output for indication to external devices e.g. BMS. The standard system controller is powered from the 3 pair loop through cable.