Sony’s Xplod line of car electronics includes CD and radio head units, subwoofers and external amplifiers. One of the connections that they offer is a remote terminal. The remote terminal on a head unit sends an electrical signal that can trigger accessory devices like power amplifiers to turn themselves on. This trigger signal makes sure that all of the additional devices that a car stereo needs are on when the system is on and turned off when the main system unit gets turned off. Writer Bio
