| 摘要 |
PURPOSE:To improve the reliability of a transmission system and to reduce the cost by supplying backup power in a group where plural terminal stations are gathered. CONSTITUTION:Terminal stations 2a-2f have a changeover device 40 comprising a relay 20 and a device secondary power supply 30. The relay 20 is driven by a terminal station power supply 10 normally in the terminal stations 2a-2f and power is supplied from a terminal station power supply 10 to the device secondary power supply 30. The terminal stations 2a-2f are grouped and each group is provided with in-group power supply lines 3a, 3b. If the terminal station power supply 10 of, e.g., the terminal station 2c is stopped, the relay 20 in the changeover equipment 40 is restored and the power is supplied from a power supply line 3a in the group to the device secondary power supply 30 of the terminal station 2c.
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