... can use O1 and other circuit to control home electrical apparatus, such as lamp, cooker, and air condition. 3) dial 2 ... can use O2 and other circuit to control home electrical apparatus, such as lamp, cooker, and air condition. 4) dial 3 ... can use O3 and other circuit to control home electrical apparatus, such as lamp, cooker, and air condition. 5) dial 4 ...