A communications system comprising: a communications unit (CPXn) comprising a first communications means for controlling communications between said communications unit (CPXn) and one or a plurality of other communications units connected to said communications unit (CPXn); and a second communications means (FTRx) for controlling communications between said communications unit (CPXn) and a client communications apparatus (HTRx); wherein said communication unit (CPXn) and said one or a plurality of other communications units are arranged to be installed in a mapped unitary flooring of a construction or in a unitary partition panel of a construction, and to be interconnected to form a communication network for serving said client communications apparatus (HTRx); characterized in that said client communications apparatus is worn on a human body and (HTRx) comprises: a transmitter main electrode provided in a location so as to readily exert an electric effect on a dielectric; and a modulator for modulating an electric potential to said transmitter main electrode in response to an electric signal corresponding to transmitted data; said client communications apparatus (HTRx) is arranged to provide to said dielectric an electric field corresponding to the modulated electric potential; said communications unit (CPXn) further comprises a receiver main electrode provided in a location so as to readily exert an electric effect on a dielectric; and said second communications means (FTRx) comprises: a measuring part for measuring an electric state of said receiver main electrode exerted by said electric field; and a demodulator for acquiring said electric signal from said measuring part and acquiring said transmitted data by demodulating said electric signal. a communications unit (CPXn) comprising a first communications means for controlling communications between said communications unit (CPXn) and one or a plurality of other communications units connected to said communications unit (CPXn); and a second communications means (FTRx) for controlling communications between said communications unit (CPXn) and a client communications apparatus (HTRx); wherein said communication unit (CPXn) and said one or a plurality of other communications units are arranged to be installed in a mapped unitary flooring of a construction or in a unitary partition panel of a construction, and to be interconnected to form a communication network for serving said client communications apparatus (HTRx); characterized in that said client communications apparatus is worn on a human body and (HTRx) comprises: a transmitter main electrode provided in a location so as to readily exert an electric effect on a dielectric; and a modulator for modulating an electric potential to said transmitter main electrode in response to an electric signal corresponding to transmitted data; a transmitter main electrode provided in a location so as to readily exert an electric effect on a dielectric; and a modulator for modulating an electric potential to said transmitter main electrode in response to an electric signal corresponding to transmitted data; said client communications apparatus (HTRx) is arranged to provide to said dielectric an electric field corresponding to the modulated electric potential; said communications unit (CPXn) further comprises a receiver main electrode provided in a location so as to readily exert an electric effect on a dielectric; and said second communications means (FTRx) comprises: a measuring part for measuring an electric state of said receiver main electrode exerted by said electric field; and a demodulator for acquiring said electric signal from said measuring part and acquiring said transmitted data by demodulating said electric signal. a measuring part for measuring an electric state of said receiver main electrode exerted by said electric field; and a demodulator for acquiring said electric signal from said measuring part and acquiring said transmitted data by demodulating said electric signal.