Apparatus and methods for deriving power from an active POTS twisted pair of lines for powering associated auxiliary electrical devices, such as signal processing electronics, includes a power supply for providing a regulated DC voltage and current, and a current regulator for limiting the current flowing in the twisted pair to a predetermined value that does not disrupt the normal signaling and operation of the telephone circuit. Another current regulator in the power supply limits the input current from the twisted pair during power surges to another predetermined value that prevents line latching in an off hook condition. A shared power arrangement derives power from a plurality of twisted pairs and powers another plurality of auxiliary electrical devices in parallel, thereby limiting the line current of any one twisted pair to a value that avoids disrupting the normal operation of the telephone circuit.