PURPOSE:To allow a radio equipment of a slave station and a radio equipment of other slave station to communicate directly by providing a means for replacing a transmission frequency and a reception frequency of a required part of a radio equipment of a slave station oppositely to those of a radio equipment of other station. CONSTITUTION:Two oscillating circuits having channel frequencies of f1 and f2 respectively are provided to a transceiver and they are switched by changeover switches SW1, SW2 interlocked with the transmission and reception section. When the radio equipments 4, 5 of slave stations communicate with each other, the channel frequency of the radio equipment of either slave station of the both is switched and the transmission frequency is taken as f1 and the reception frequency is taken as f2, then the direct communication between the two slave stations is attained. As the method expanding the range as shown in a large circuit of radius R, a threshold value in an outer line talking connection where the S/N of a received output is detected for >=20dB and it is regarded as the presence of an incoming call is decreased to 10dB in the extension connection or the transmission output is increased.