| 摘要 |
PURPOSE:To set key telephone sets for a power failure and its number and the backup time of a battery optionally by referring to the contents of a storage means in case of the occurrence of a power failure, and performing the same normal control as the during the feeding of a main power source for a specific key telephone set and small electric power control in which power consumption is reduced for other key telephone sets. CONSTITUTION:An AC commercial power source AC used as the main power source is stabilized by a power circuit (PS)17 after the voltage of the current is stepped down, and then supplied as a local power source E to respective parts. The battery (B)18 is provided for the PS17 and feeds electric power when the commercial power source AC enters a power failure state to back up the telephone set. When the power failure of the commercial power source AC occurs, its detection signal is supplied to a CPU14, which checks a specific key telephone set (ST) to judge a ST4 for a power failure as a specific sST, and then sets telephone set interfaces (TIF)13 corresponding to other STs in a lower power control state. |
