A radio-signal-responsive vehicle device control system including a receiver unit (9, 41, 74, 100) for receiving a radio signal generated based on a signal transmitted from a calling telephone unit and for generating a detectable signal based on the received radio signal, receiver unit storage structure...http://www.google.co.uk/patents/US5113427?utm_source=gb-gplus-sharePatent US5113427 - Radio-signal-responsive vehicle device control system
