Abstract: In a system for transmitting a charging signal from an exchange to a telephone system together with a voice signal, radio equipment in the exchange side detects the charging signal sent from the exchange and encodes it into a pulse code signal comprising a plurality of continuous pulses. Thereafter, this pulse signal is modulated into a frequency signal outside the voice transmitting frequency band and then transmitted as a radio signal after it is superimposed on the voice signal. Radio equipment on the telephone side detects this charging signal carrier and demodulates it into the pulse code signal, then counts it and transfers the charging signal when the counted value reaches a specified value.