Abstract: A load management system for monitoring the output from a power supply and managing the load on said power supply, said load management system comprising a hysteresis circuit for signaling a load element to stop drawing current when an output voltage at said output falls below a first threshold and for signaling said load element to resume drawing current when said output voltage rises above a second threshold, said hysteresis circuit comprising a first state sensing circuit having an input coupled to said output and for signaling whether said output voltage is greater than or less than said first voltage threshold, a second state sensing circuit having an input coupled to said output and for signaling whether said output voltage is greater than or less than a second voltage threshold, and a state transition circuit having a first input coupled to the output of said first state sensing circuit and a second input coupled to the output of said second state sensing circuit, said state transition circuit having a

Abstract: A telephone transmission system in which a telephone transmission line connects a central office d.c. power source to a battery charging control circuit to apply an input voltage to the control circuit, in which a battery charger connects a rechargeable battery to said control circuit to draw battery charging current from the transmission line under the control of the control circuit, in which the control circuit is rendered effective by a lowering of the input voltage to at least a predetermined value to effectively disconnect the battery charger and the battery from the transmission line for a period that exceeds the interval in which the input voltage is lowered.