Electronically switched optically coupled line interface

摘要

An optocoupled line circuit is arranged with a diode bridge providing uniform direction current flow so as to eliminate the mechanical switch hook contact of the prior art. A zener diode is used to bridge a clipped version of AC ringing current across the optocoupler when the circuit is in the on-hook condition. Current presented to the optocoupler from a line control device allows current to flow from the telephone line through the line interface circuit.