Automotive host device, motor vehicle terminal and method for connecting the same

There is described a motor vehicle host device to connect at least a motor-vehicle terminal. The motor vehicle-host device comprises a power supply circuit for the terminal and an interface for connecting a terminal to the host device, wherein said interface comprises a detection contact. The host device further comprises a first circuit which is adapted to detect a voltage change on a connected to the detecting contact line and outputting a voltage change signal characterizing, and a second circuit which is arranged, which to detect the change in voltage characterizing signal and in response to activate the power supply circuit of the detected signal on or off. Further, a motor-vehicle terminal device is disclosed for connection to an automotive host device.