Patent ID: 7020277

Claim:
A line interface for coupling a data transceiver to a transmission line having a load impedance Z via a transformer having a turns ratio of 1:n, said data transceiver transmitting signals in a first frequency range and receiving signals in a second frequency range different from said first frequency range, said line interface comprising: an input port for receiving an input signal voltage from a circuit formed on an analog front end (AFE) chip; an output port; a line driver coupled between said input port and said output port, said line driver amplifying the input signal voltage and supplying an amplified signal as a transmit signal to said output port; a line port for sending the transmit signal to and receiving a receive signal from the transformer; termination resistors coupled between said output port and said line port; a receive signal port for supplying the receive signal to said AFE chip; a receive amplifier formed on said AFE chip, coupled to said receive signal port; and a bridge network including a first pair of resistive paths resistively coupling said line port to said receive signal port, and a second pair of resistive paths resistively coupling said output port to said receive signal port, said bridge network having a low-pass filter characteristic, wherein said first pair of resistive paths are coupled each other via a capacitor provided therebetween, and said second pair of resistive paths are coupled each other via a capacitor provided therebetween.