PURPOSE: To attain the talking through telephones by transmitting a call signal with a radio telephone device which the states of slave devices can be monitored by a master device only in case the slave devices are set in the waiting state when the master device receives the call signal.

CONSTITUTION: The carrier signal transmitted through an antenna 23 of a master device 1 is supplied to a reception circuit 25 through an antenna 24 of the 1st salve device. The carrier signal received by the circuit 25 is partially detected by a carrier wave detecting circuit 23 to actuate temporarily a transmission circuit 29 in case the 1st slave device is set under a waiting state. Then the carrier signal is transmitted through an antenna 34 and received by a reception circuit 22. Then the carrier signal is applied to a control circuit 3 via the 1st detection circuit 7 to discriminate that the 1st slave device is kept in the waiting state. Then a call signal control part is controlled and a call signal oscillator 10 is oscillator to supply a call signal to the circuit 29. Then said carrier signal is modulated and transmitted through the antenna 23.