| 摘要 |
PURPOSE:To reduce power consumption by adding a switch circuit to a current limiting circuit, and turning on and off a switching circuit under the command of the control part of a subscriber circuit and supplying and cutting off electric power. CONSTITUTION:When data communication is carried out between the multifunction telephone set and subscriber circuit, the control part LPRa detects, for example, a parity check defect occurring twice successively, and then disconnects one terminal of resistance R7 from the ground to cut off a current flowing to the light emission part of a photocoupler PH and turns off a photodetection part to turn off a transistor (TR), stopping power supply. When the communication is restarted, the control part LPRa grounds the one terminal of the resistance 7 and flows a current to the light emission part of the photocoupler PH to start the multifunctional telephone set TEL. |
