Method of and circuit arrangement for evaluating the output signals of current flow detectors in telecommunication facilities

Abstract From the Canadian patent

PHD 85-358 17-11-1986, ABS, "Method of and circuit arrangement for evaluating the output signals of current flow detectors in telecommunication facilities". The flow of a loop direct current and/or a dialling alternating current can be detected in telecommunication facilities by means of current flow detectors. The output signals produced by the current flow detectors are applied to an evaluation circuit the, zero-crossing of the dialling alternating currents being used to determine whether a dialling alternating current has been superimposed on the loop direct current. In order to increase the evaluation security and to detect noise voltages coupled into the subscriberconnecting line, the …