PURPOSE: To shorten frame synchronizing recovery time as an entire system by outputting a data signal inputted to a signal processing circuit as it is when out of frame synchronism of a frame synchronizing circuit is caused.

CONSTITUTION: The repeater is provided with a receiver 1, a demodulator 2 demodulating an output of the receiver 1 and outputting a received section 3 applying signal processing to the received data signal dr and outputting the transmission data signal dr, a modulator 4 outputting a modulation signal modulated by the transmission data signal dt and a transmitter 5 sending the output of the modulator 4. When frame synchronizing step-out takes place, the data signal inputted to each signal processing circuit requiring the frame signal is outputted as it is. Thus, the acquisition of the frame synchronizm is attained in parallel at the same time without awaiting the re-establishment of the frame synchronization of a preceding station by each succeeding station to an intermediate station and the intermediate repeater station whose frame synchronism is stepped-out. Thus, the frame synchronizing recovery time as the entire system is shortened.