A vehicle mounted communication system comprises a hand held mobile phone and a hands-free unit. The hand-held unit includes a wide area transceiver for station outside of the vehicle and a short-range radio transceiver the hands-free unit includes a microphone and speaker and is mounted in a fixed location...http://www.google.de/patents/US6542758?utm_source=gb-gplus-sharePatent US6542758 - Distributed radio telephone for use in a vehicle
