| 摘要 |
PURPOSE:To make easy the increase of current capacity and power supply of different voltage simply, by duplicated power supply through the use of channels and data lines between a master set and telephones. CONSTITUTION:A master device 21a and a telephone set 22a are connected with channels 23a and data lines 24a. The channel 23a is connected with a power supply 26a and a power supply circuit 33a via switches 29 and 31 selectably, and with the change-over of the switches 29, 31, the connection between a channel side terminal 25a and the channel and the connection between the power supply circuit 26a and the power supply 33a are mde alternately. On the other hand, transformers 30a, 35a between a data line 24a and data circuits 27a and 36a are connected with a power supply circuit 28a and a power supply circuit 37a, and the power of the power supply circuit 28a is fed to a power supply circuit 37a. An output 38a of the power supply 37a is supplied to modulation and demodulation circuits and control circuits and an output 34a of the power supply circuit 33a is supplied to a tone ringer circuit and an audio callout circuit. |
