Use a Simplex fire alarm control unit (FACU) IDNAC signaling line circuit (SLC) to individually power, address, and control wall mount indoor and outdoor addressable S/V notification appliances. Use a separate compatible Simplex FACU audio NAC for audio. The electronic monitoring of wiring supervision means you can T-tap audio and IDNAC wiring for Class B wiring, reducing wiring costs and wiring distances. Install on standard 4 in. square 2 1/8 in. deep USA electrical boxes for flush installations, provided by others, or surface or weatherproof (WP) backboxes, see Table 15, for surface or WP installations.