| 摘要 |
PURPOSE:To obtain many functions by combinations with various external devices by modulating a carrier with various signals except a speech signal and transmitting and receiving the various signals mutually. CONSTITUTION:When the talk button 10 of slave equipment 1 is pressed, its signal is inputted to a control part 39, which sends a call signal out of an output circuit 49A and the signal is modulated by a signal modulator 49 to a frequency close to the frequency component of a voice. The call signal after being modulated by the modulator 49 is made into a carrier signal by a modulator 44, and the signal is sent out to a power line 3 through an amplifier 41 and a coupler 40. The carrier signal sent out of the slave equipment 1 is sent to a demodulator through the coupler and filter of master equipment and the call signal from the demodulator passes through a signal demodulator for restoring the signal to original data, which is inputted to the interruption input circuit of the control part. |
