| 摘要 |
PURPOSE:To simplify circuit constitution and to constitute the circuit of economical parts by changing a sending level for each key to send a signal, and on the receiving side, discriminating the level and actuating a relay corresponding to the depressed key. CONSTITUTION:A keyboard 1 in a transmission part 1 is connected to a voltage discriminating circuit 2 in a receiving part through two lines l1, l2 and the output of the voltage discriminating circuit 2 is connected to a relay part 3. The voltage Vcc and one terminal of switches S1-Sn of the keyboard 1 is connected to the line l respectively. A level detecting integrated circuit 6 in the voltage discriminating circuit 2 receives a signal from the keyboard through the line l2. When the switch S2 is depressed, 3.8V voltage is sent to the line l2 and the level detecting integrated circuit 6 sends a signal through a line l4. Consequently, a relay 13 receives the signal through the line l4 and is driven to control an electric apparatus or the like corresponding to the relay 13. |
