| 摘要 |
PROBLEM TO BE SOLVED: To achieve power saving by detecting actuation of two units, i.e. a slave unit and an individual identification unit, through one voltage detection circuit in a living room master unit. SOLUTION: The slave unit (1) and the individual identification units (5, 10) are connected with the living room master unit (3) called from the slave unit through a transmission line (L) and talking over the interphone. The living room master unit comprises a voltage detection circuit (41) for detecting voltage variation due to calling operation with the slave unit (1) and identification operation with the individual identification units (5, 10), and a master unit CPU (44) performing power supply control of an individual identification unit side data transmitting/receiving circuit (38) for transmitting/receiving data to/from the individual identification unit (5) when calling operation is performed with the slave unit (1) on the basis of the detection result from the voltage detection circuit (41), and when identification operation is performed with the individual identification unit (5) and a slave unit side data transmitting/receiving circuit (37) for transmitting/receiving data to/from the slave unit (1). COPYRIGHT: (C)2007,JPO&INPIT
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