PROTECTIVE DEVICE FOR DIGITAL COMMUNICATION LINE

摘要

PURPOSE: To achieve high quality transmission of various kinds of signals regardless of the existence of modulation or the superimposition of a d.c. signal by transmitting a pulse signal and a modulated digital signal or a modulated analog signal through an insulated coil and transmitting them through a neutralizing coil when a d.c. signal is superimposed. ;CONSTITUTION: An unmodulated digital signal or a modulated digital signal such as PCM and various kinds of analog signals by an FDM system are transmitted from line side terminals L₁₁, L₁₂ to an insulated coil IT₁, and equipment side terminals T₁₁, T₁₂ or from equipment side terminals T₂₁, T₂₂ to line side terminals L₂₁, L₂₂ through an insulated coil IT₂. A d.c. signal superimposed between lines is transmitted from the terminals L₁₁, L₁₂ to the terminals T₁₁, T₁₂ through a neutralized coil NT₁ or from the terminals T₂₁, T₂₂ to the terminals L₂₁, L₂₂ through a neutralized coil NT₂. Further, abnormal current and voltage due to a lightning surge or the like from a communication cable side are released to a remote grounding terminal Ei through arresters A₁, A₂, A₅, A₆.;COPYRIGHT: (C)1995,JPO