| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable application/interruption control of a main power source of an electronic device without using a power supply control signal line, and to prevent a drawback of interrupting the main power source due to temporary fault of the optical line. <P>SOLUTION: An optical line monitoring circuit 136 receives power source supplied from a standby power source 138 and always monitors the state of the optical line 11. A power source control circuit 137 operates by receiving the power supply from the standby power source 138, and performs switching operation for application of the main power source according to actuation detection of the optical line 11 by the circuit 136. A main circuit 132 operates by the application of the main power source, and issues an interruption preparation request to the circuit 137 upon receiving an interruption request command from the optical line 11. Only when this interruption preparation request is issued, the circuit 137 performs a switching operation for main power source interruption in response to stoppage detection of the optical line 11 by the circuit 136. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
