| 摘要 |
PURPOSE:To prevent to increase an applied current of respective key telephone sets and to make small current capacity of the parts in a power source part of a main device and to make the power source pat widely small and low-priced by starting to supply power source from a main device to key telephone sets at the fixed time interval in a time series. CONSTITUTION:When power source is applied, power source from a power source part 3 of a main device 10 is supplied to data oerlapping parts 41, 42,-4n corresponding to respective key telephone sets 71, 71,-7n. Power source supplying switch parts 51, 52,-5n are kept in an off condition. After applying power source, when a fixed time passes, a main control part 1 starts to operate and a control signal is sent to a power source supplying control part 2. The power source supplying control part 2 receives the control signal, sets the power source supplying switch part 51 to a connected condition and power source from the power source part 3 is supplied to the key telephone set 71. further, when the fixed time (time till applied current of the key telephone set 71 ends) passes, the control part 2 sets the power source supplying switch part 52 to a connected condition and supplys power source to the key telephone set 72. Hereinafter, the control is successively executed until No.n power source supplying switch part 5n is reached. |
