1. A differential termination and attenuator network having an automated common mode termination voltage generator receiving a DC common mode voltage from a voltage source having source resistances and coupled to a differential amplifier comprising: first and second input termination resistances having a common node and respective input nodes receiving the DC common mode voltage from the voltage source; first and second attenuators having a common node and respective input nodes and output nodes with each respective input node coupled to one of the first and second input termination resistances; a monitoring circuit coupled to the input nodes of the first and second input termination resistances for generating an output signal representative of the combination of the DC common mode voltage on the input source resistances and voltage representative of an adjustable termination voltage on the input termination resistances; an automated termination voltage generator receiving the output signal from the monitoring circuit and generating the adjustable termination voltage substantially equal to the DC common mode voltage on the input source resistances; and a control circuit receiving the adjustable termination voltage and the monitoring circuit output signal and generating a scaled termination voltage and drive current and a scaled compensation voltage and drive current that are a function of the adjustable termination voltage and the DC common mode voltage with the scaled termination voltage and drive current coupled to the common node of the first and second input termination resistances and the scaled compensation voltage and drive current coupled to the common node of the first and second attenuators for providing DC currents through the first input termination resistance and first attenuator and the second input termination resistance and second attenuator for nulling DC currents at the input nodes of the first and second input termination resistances and provides a DC common mode voltage at the output nodes of the first and second attenuators for optimizing the dynamic range of the differential amplifier.