| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device which can easily be charged from a main device on a slave machine-side in a wire paging system which is composed of a main device, a plurality of slave machines, a speaker and a connection cable, in which the other slave machine is called by the speaker through a broadcast line of the main device from the slave machine with supply of DC current from the main device and a call between the slave machines is made through a call line. SOLUTION: A commercial power frequency oscillation circuit OSC1 and a broadcast state detecting circuit detecting presence of a use state of the broadcast line P or the call line B are arranged in the main device M. The power supply device V having a battery that can be charged through the broadcast line P when the broadcast line P is not in the use state is disposed in the slave machine H. When the broadcast line P or the call line B is in the use state, the commercial power frequency oscillation circuit is interrupted to be connected to the broadcast line. When the broadcast line or the call line is not in the use state, the commercial power frequency oscillation circuit is connected to the broadcast line and the power supply device V is charged. COPYRIGHT: (C)2006,JPO&NCIPI |
