Telephone instrument with remote listening unit - uses earphones with radio receiver and transmitter in instrument modulated by speech signal

摘要

The telephone instrument has a remote listening unit for reproduction of received signals. The unit consists of earphones (OH), and of a radio transmitter (S) in the telephone instrument with a modulator. The circuit is used for modulating the transmitter with signals received from the telephone network. A receiver for the radio signals and a demodulator are integrated with the earphones, so that the radio signals are demodulated and applied to the earphones.