| 摘要 |
PURPOSE:To reduce the reply time and to attain the communication without malfunction by providing a tone detection means to a base station, providing a control switch to a remote controller so as to make it conductive only when a tone is detected. CONSTITUTION:When a radio signal is sent from a mobile station 7, it is received and demodulated by the reception circuit 9 of a base station 8 and led out of a line 10. A noise squelch circuit 14 closes a switch 11 in this case. Then a data signal is given to a remote controller 29 from lines 27, 28, processed by a signal processing circuit 42 and the result is displayed on a display circuit 43. In detecting a tone signal, a tone squelch circuit 16 brings the line 17 to the H level. Thus, a photocoupler 23 of the remote controller 12 is operated. Thus, a DC current is conducted during tone detection period through the route of the controllers 12, 29, a transistor 38 is conductive and a control switch 44 is closed. Thus, a sound signal from the secondary winding 39 of a transformer 30 is converted to audio by a speaker 45. |
