RADIO COMMUNICATION SYSTEM, ANTENNA DEVICE AND COMMUNICATION TERMINAL EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a communication system which can easily be loaded on a vehicle and realizes bi-directional communication. SOLUTION: Radio communication equipment is divided into communication terminal equipment 20 and an antenna device 10 and they are connected by one cable 30. A transmission/reception signal processing circuit 21 arranged in communication terminal equipment 20 processes transmission/reception signals and generates a transmission/reception switch signal giving the instruction of the switching of transmission/reception. A voltage control circuit 23 outputs the first voltage signal or a second voltage signal of power different in a voltage based on the transmission/reception switch signal. A control signal generation circuit 17 disposed in the antenna device 10 generates a control signal based on the voltage of the first voltage signal or the second voltage signal. A first switch circuit 12 and a second switch circuit 13 selectively switch/connect a reception circuit 15 and a transmission circuit 16 to an antenna element 11 based on the two control signals.