| 摘要 |
PROBLEM TO BE SOLVED: To compose a network of network equipment using Ethernet, without any Ethernet-dedicated transmission line by detecting an AC data signal on a house power wire with a voltage close to the maximum value of a full-wave rectified signal in three states of presence, absence, and collision. SOLUTION: A mixed AC signal waveform is inputted from a house power wire 1 to a high-pass filter 7, and an AC source voltage signal waveform is subtracted to obtain an amplified AC data signal waveform. This is inputted to an attenuator 8 and attenuated with the amplification factor of an amplifier 17 of an output circuit 4 to obtain an AC data signal waveform, which is inputted to a data absence comparator 11, a data presence voltage comparator 11, and a data collision voltage comparator 12 and is compared with a voltage close to the maximum voltage value of the waveform. Then the three states of data presence and absence, and collision on the house power wire 1 are detected. The detected states are inputted to an existent Ethernet adapter circuit 5 through a data control line 19 and are used as the criterion for CSMA/CD transmission control.
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