An input circuit for an alternating current, AC, signal from a pair of elongated conductors that extend for a distance of at least 30 meters, said input circuit comprising: an interface structured to output a logic signal obtained from square waves corresponding to zero-crossings of the alternating current signal of said pair of elongated conductors; a load switchable to said pair of elongated conductors; characterized by a processor structured to: (i) output a control signal to switch said load to said pair of elongated conductors asynchronously with respect to said alternating current signal for a first predetermined time, (ii) input the logic signal, (iii) determine (15 8,160,162,164) if the input logic signal is active a plurality of times, according to a predetermined count, during the first predetermined time and responsively set a first state of said alternating current signal, and, otherwise, set an opposite second state of said alternating current signal, and (iv) delay repeating said output for a second predetermined time, if the opposite second state of said alternating current signal is set, and, otherwise, delay repeating said output for a third predetermined time, which is longer than the second predetermined time, if the first state of said alternating current signal is set. an interface structured to output a logic signal obtained from square waves corresponding to zero-crossings of the alternating current signal of said pair of elongated conductors; a load switchable to said pair of elongated conductors; characterized by a processor structured to: (i) output a control signal to switch said load to said pair of elongated conductors asynchronously with respect to said alternating current signal for a first predetermined time, (ii) input the logic signal, (iii) determine (15 8,160,162,164) if the input logic signal is active a plurality of times, according to a predetermined count, during the first predetermined time and responsively set a first state of said alternating current signal, and, otherwise, set an opposite second state of said alternating current signal, and (iv) delay repeating said output for a second predetermined time, if the opposite second state of said alternating current signal is set, and, otherwise, delay repeating said output for a third predetermined time, which is longer than the second predetermined time, if the first state of said alternating current signal is set. (i) output a control signal to switch said load to said pair of elongated conductors asynchronously with respect to said alternating current signal for a first predetermined time, (ii) input the logic signal, (iii) determine (15 8,160,162,164) if the input logic signal is active a plurality of times, according to a predetermined count, during the first predetermined time and responsively set a first state of said alternating current signal, and, otherwise, set an opposite second state of said alternating current signal, and (iv) delay repeating said output for a second predetermined time, if the opposite second state of said alternating current signal is set, and, otherwise, delay repeating said output for a third predetermined time, which is longer than the second predetermined time, if the first state of said alternating current signal is set.