| 摘要 |
PURPOSE:To reduce wiring by providing a receiving means which superposes a channel selecting address signal onto a low-power AC power supply line to report that a channel corresponding to its own address is called. CONSTITUTION:A carrier wave controlling unit 12 is provided for the low-power AC power supply line and communication lines 11. A power supply part 25 rectifies the AC of said power supply line. A zero crossing pulse is generated and is outputted to a logic control part 22 for timing of transmission and reception. A coupling circuit 26 has a high frequency oscillating part 27 and a switch circuit 28 and outputs a high frequency between terminals (a) and (b). High frequency components transmitted on these lines 11 are detected and are inputted to the logic control part 22. A selecting address is set by a channel setting part 29, and this set data and data of a received channel selecting address signal are compared with each other in a logic control circuit part 24 and a relay driving circuit part 25 are driven to switch communication lines by a changeover switch 13. |
