Ringing subscriber line interface circuit with full differential analog interface

Abstract

A fully differentially based analog interface is used to couple a (ringing) subscriber line interface circuit (SLIC) to a dynamic range-constrained circuit, such as a low voltage codec. In the receive direction, and for ringing signal generation, an operational amplifier has its inputs differentially coupled to first and second polarity signal input ports; the amplifier's output is coupled to a single ended node of the internal circuitry of the respective port. In the output signal direction for transmission, a single ended output node of the internal circuitry of the respective SLIC circuit function is coupled to each of a pair of opposite polarity buffer paths, terminated by differential polarity output ports.

Dependencies are inferred from the claim text.