| 摘要 |
<p>PURPOSE:To attain a communication action with respective communication equipments even at the time of the power failure by providing a power source supplying means to supply a power source at the time of a commercial power source power failure in a controller and supplying the power source only to the communication equipment executing the communication among plural communication equipments. CONSTITUTION:When a calling comes from a trunk line at the time of a power failure, a power failure-time ringer circuit 4 is operated by the calling signal voltage and rings a bell sound. When an operator hooks off a telephone set 2, a switch A (SWA) is closed by interlocking to a hook switch (HS) and by the direct current voltage overlapped to a data line 1c by a power failure-time power source supplying circuit 10, a dial circuit 12 and a telephone circuit network 13 go to an action condition. Thus, calling is possible and even when the calling comes from the telephone set 2, the dial circuit 12 and the telephone circuit network 13 go to the action condition in the same way by the off-hook and the dial calling and communication are attained.</p> |
