PURPOSE: To prevent the deterioration of S/N of an FSK signal in multirelaying, by applying waveform shaping to an RC signal in a relay station for improving the S/N.

CONSTITUTION: An SV signal demodulated and extracted at a receiving circuit 1 is separated into an OW signal and an FSK signal via both a low pass filter 3 and a band pass filter 4 at the receiving side, and the RC signal is extracted from the FSK signal at an FSK demodulator 6. The said RC signal is shaped into a waveform equal to that of the RC signal at a pulse shaping circuit 10. The shaped RC signal is inputted to a gate circuit 11 and goes to the FSK signal again via an FSK modulator 8. A transmission circuit 9 applies FM modulation to a carrier wave which is applied with RCM modulation by the SV signal synthesized by the OW signal and the FSK signal and transmits the result to the next station. Further, the OW signal is an order telephone signal between relay stations, the RC signal is a control signal to monitor and control remotely each relay station, the FSK signal is a signal applying the frequency shift modulation to the RC signal, and the SV signal is a signal synthesized with the OW and the FSK signals.