Cordless transmitting and receiving apparatus

Claim 1

A cordless transmitting and receiving apparatus which is capable of providing transmitting and receiving between a key transmitting and receiving apparatus as a fixed station and a portable remote transmitting and receiving apparatus and in which a transmission signal from the key transmitting and receiving apparatus is received in the remote transmitting and receiving apparatus by electromagnetic induction through a commercial AC power line, said remote transmitting and receiving apparatus comprising a transmitting station including an aural signal transmitting circuit and a first antenna for transmitting an output signal of said circuit and a receiving station including a second antenna electromagnetically coupled to an AC line and a receiving circuit for converting the output signal of said second antenna into an aural signal to put out the latter, said key transmitting and receiving apparatus comprising a receiving circuit electrically connected to the AC line, a signal shunt for transmitting an output signal of said receiving circuit to an external telephone line and a transmitting circuit for putting out the transmission signal from said external telephone line to the AC line through the signal shunt circuit, said cordless transmitting and receiving apparatus further comprising a relay transmitter including a third antenna for receiving an output signal of the first antenna of the remote transmitting and receiving apparatus, a frequency converter for frequency-converting the output signal of said third antenna and connection means for applying the output signal of said frequency converter to the AC line.