Long subscriber loops using automatic gain control mid-span extender unit

Abstract

Systems and methods are described for long subscriber loops using automatic gain control. A method includes extending a digital subscriber loop including: producing an output signal in a first direction from a variable gain amplifier at a mid-span extender unit responsive to an input signal in the first direction from the digital subscriber loop; monitoring a signal strength of said output signal in the first direction at the mid-span extender unit; generating a gain control signal responsive to the signal strength at the mid-span extender unit; controlling a gain of the variable gain amplifier at the mid-span extender unit responsive to the gain control signal; and controlling a second gain of a second variable gain amplifier at said mid-span extender unit responsive to said gain control signal to produce an output signal in a second direction from said second variable gain amplifier at said mid-span extender unit responsive to a second input signal in said second direction from said digital subscriber loop.