| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system that connects electronic apparatuses by two electric wires and simultaneously supplies electric power and communicates signals through the two electric wires, the communication system having simple circuit constitution and using thin electric wires. SOLUTION: The electric apparatuses are connected together by using the two electric wires and the supply of DC power and signal communication are carried out by superposing a binary signal on the DC power. Each of the electric apparatuses is equipped with a communication circuit for signal communication. A sent signal output terminal of the communication circuit has three states which are states of first and second voltages corresponding to the high level and low level of the binary signal and a state of high impedance. The sent signal output terminal of the communication circuit is connected to one of the two electric wires through a parallel circuit of a resistance and a capacitor. Each of the electric apparatuses which are supplied with the electric power is equipped with a DC-DC converter which converts the voltage of the received DC power into a source voltage for its apparatus. The voltage of the DC power sent through the two electric wires has a mean value of the first voltage and second voltage. COPYRIGHT: (C)2007,JPO&INPIT
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