Our Refuge master controllers starts from 4 to 224 line 'Compact' system comprises two wall-mounting master controllers (the ECU-4 , ECU-8 and ECU-16 which can handle 4, 8 and 16 lines) and an eight-line expansion unit (the ECU-8S). Typically located in a building's control room or fire services access point, the ECU-4, ECU-8 and ECU-16 allow emergency personnel to communicate via a telephone-style handset with the system's 'outstations' with true full duplex speech communication.