Abstract: An alarm system having improved acoustic signal transmitting capability is provided for motor vehicles. The radio speaker system of the vehicle is employed for both passenger listening and for warning signal transmission in the event of unauthorized intrusion or attempted theft. The speakers occupy their usual installation positions in a vehicle, such as horizontally mounted in the dashboard, when used for the purpose of listening to a radio or tape. When the vehicle is unoccupied, and theft or tampering are attempted, an alarm system is activated which causes a control element to swivel the speaker into a position parallel to an external surface of the vehicle. Due to this repositioning of the speaker, reflection of an alarm signal back into the interior of the vehicle is minimized, and transmission of the alarm signal to the outside of the vehicle is optimized.

Abstract: A central locking system with a two-door control for motor vehicles, in which certain locking operations are precluded in dependance on the position of the key of a starter switch of the driving engine. In order to prevent an unitentional locking of the vehicle doors under certain operating conditions, means are provided according to the present invention which enable a locking actuation of the central locking system exclusively by the interior actuating element of the driver door on the steering column side when the key is in the starter whereas only a mechanical locking of the individual front door on the passenger side is possible by way of the interior actuating element of this passenger door.