| 摘要 |
A control unit inquires each digital apparatus stored in a memory table in a memory about a power supply mode of the apparatus through an IEEE1394 serial bus. When a response indicates a power-on mode, corresponding icons 61 - 1 and 61 - 2 are normally displayed. When the response indicates a connection standby mode, a corresponding icon 61 - 3 is mesh-displayed. If there is no response, corresponding icons 61 - 4 and 61 - 5 are inversion-displayed. A connection detecting circuit 111 detects a bias voltage of an IEEE1394 serial bus 101 and outputs a detection signal to a main control circuit 122 . On the basis of the input detection signal, the main control circuit 122 controls a power supplying circuit 117 so as to supply a standby electric power to a standby power supplying circuit 116 . On the basis of a command from the main control circuit 122 , the standby power supplying circuit 116 supplies a standby electric power to a physical connecting circuit 112 , a logical connecting circuit 113 , and a standby control circuit 121.
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