| 摘要 |
PURPOSE:To insulate communication facilities electrically and perfectly by utilizing the insulating property of an optical fiber cable, to transmit an electric signal with an electrooptical converter while securing insulation between an electric center and a communication line. CONSTITUTION:A PCM coding device 162 converts a signal from a telephone circuit into a PCM code, whose electric signal is converted into an optical signal through an electrooptical signal converter 166. Further, the PCM-coded optical signal is converted into an electric signal through an electrooptical signal converter 167. Then, a PCM decoding device 163 decodes the PCM code. Thus, communication facilities are insulated electrically and perfectly from a rise in ground potential during grounding, the intrusion of a lightening surge from a communication line, etc. |
