Patent ID: 7212627

Claim:
A line interface for use in a transceiver system, the line interface comprising a hybrid circuit including a single transformer and a single matching circuit, the transformer couplable on a primary side to a transmit amplifier and to a receive amplifier and couplable on a secondary side to a communication medium, each side of the transformer having split windings, each half of the primary side further split into a first winding having a first number of turns and a second winding having a second number of turns, the first winding and the second winding coupled in series on each half of the primary side, the single matching circuit having a matching impedance less than a line impedance and coupled in parallel between the first windings and the second windings on each half of the primary side, the line interface further comprising a multiple negative-feedback network for causing the matching impedance to appear larger than its actual value as seen by the communication medium on the secondary side and to appear with its actual value at the output of the transmit amplifier.