Loop, dial pulse and ring trip detection circuit with capacitive shunt network

摘要

A circuit which detects the presence and absence of a telephone subscriber loop, before and after ringing current is applied to the loop. Coils functioning as magnetic field generating devices and a Hall effect device are used to perform the detection function. Inclusion of a capacitive shunt network limits the responsiveness of the Hall effect device during ringing, permitting use of the device on lines to which multiple ringers are connected.