| 摘要 |
PROBLEM TO BE SOLVED: To provide an interphone system whereby a living room master unit of one model can be connected to a plurality of entrance slave units independently of the number of connected units and each entrance slave unit and the living room master unit can make a speech with each other. SOLUTION: The living room master unit 2 includes a switching control circuit 29 that controls a power supply switch 33 to be turned off to interrupt a power supply path when a prescribed speech time counted by a speech timer 27 expires or the living room master unit 2 makes a speech termination operation, and each of the entrance slave units 1a to 1n includes a latch circuit 16 that releases a memory of a call state and changes into a memory of a standby state when the power supply path is interrupted. COPYRIGHT: (C)2007,JPO&INPIT
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