| 摘要 |
PURPOSE:To utilize maximizingly the merit of plural automobile telephone systems by switching the system automatically depending whether a call is an outgoing call or an incoming call. CONSTITUTION:A transmitter-receiver 2C outputs a call signal in the case of making a call. The call signal is inputted to a connection system decision means 21, from which a control signal is outputted to a control terminal 112 of changeover means 13, 14. Then a 2nd system control means 12 connects to the transmitter-receiver 2C and a transmission reception means 15. An electric field strength discrimination means 16 discriminates whether or not the electric field strength of the radio wave of the connected system (1st or 2nd system) is sufficient for the relevant communication. When not sufficient, 'out of zone', information is outputted to the connection system decision means 21. Thus, the connection system decision means 21 outputs a control signal outputs a control signal to the control terminal 111 of the changeover means 13 and 14 to throw the contacts. |
