Radio control over a distance beyond the arriving distance of the
conventional radio control and transmission of the continuous instruction
signal on the real time are possible. The system provides DTMF signal
generation means for modulation of a control signal for controlling a
controllable section into DTMF signal, VOIP transmission means for
receiving DTMF signal to generate VOIP signal for transmission to VOIP
line, VOIP line capable of transmitting VOIP signal, VOIP receiving means
for receiving VOIP signal for conversion into DTMF code, DTMF
demodulation and retransmission means for conversion of regenerated DTMF
signal into a radio control transmission signal and a controllable
section for receiving the radio control transmission signal and the
signal generated by DTMF signal generation means is driven by DTMF
demodulation and retransmission means through VOIP line in order to
control the receiving means.