Abstract: A telephone station repeater is disclosed which will provide bidirectional gain in a long telephone loop at the customer's station. The repeater is powered from the central office battery over the loop and provides gain with very small power consumption and virtually no power consumption when not in use.The station repeater comprises a negative impedance amplifier including a shunt negative impedance, a series negative impedance and an autotransformer connected in a .pi. configuration. The shunt converter is disconnected when the telephone set is on-hook. The autotransformer provides impedance matching to the telephone set.

Abstract: A telephone Range Extender with Gain (REG) is disclosed for extending the range of loop lengths over which telephone service can be provided. This is accomplished by providing voice frequency gain, a higher voltage talking battery, and supervisory and signaling circuitry for increasing the level of supervisory and signaling currents at the central office end.The range extender requires no adjustment for loops of different lengths. A .pi. configuration negative impedance amplifier includes an adjustable gain circuit responsive to the resistance of the connected loop to automatically adjust the gain of the amplifier to the length of the loop. At the same time, an impedance matching circuit is transformer-coupled to the loop. The frequency shaping of the negative resistance amplifier and the impedance matching network, when reflected through the transformer, provides acceptable impedance matching for a wide range of loop lengths and wire gauges.