Herein disclosed a communications system according to the present invention comprises, a wireless microphone transmission apparatus for transmitting a radio microphone signal on a predetermined wireless microphone frequency channel carrying a voice signal and a tone signal; and a wireless receiving apparatus for receiving the radio microphone signal on the predetermined wireless microphone frequency channel carrying the voice signal and the tone signal transmitted by the wireless microphone transmission apparatus. The wireless receiving apparatus includes an integral computing unit for sequentially computing integrals of the signal levels of the tones of the tone signal at first predetermined time intervals and a data information computing unit for sequentially computing differences between two respective integrals of the signal levels of the tones of the tone signal, at respective second predetermined time intervals to acquire data information.