WIRELESS SPEECH SYSTEM WITH MONITOR

摘要

PROBLEM TO BE SOLVED: To provide a wireless speech system with monitor that requires no 2/4 wire conversion circuit and attains 2-way speech using a 2-wire communication line. SOLUTION: A doorphone slave set D with camera is connected to an interphone master set E with monitor with a wired line, a voice signal is frequency- modulated and transmitted between the doorphone slave set D and the interphone master set E with monitor, the video signal is transmitted as a base band, the interphone master set E with monitor transmits the frequency- modulated voice signal and the video signal to an interphone sub master set F with monitor through a radio channel, and the interphone sub master set F with monitor transmits the frequency-modulated voice signal to the interphone master set E with monitor through a radio channel.