Patent ID: 7103013

Claim:
A data communications system including a bidirectional buffer coupled among a transmitter, a receiver, and a transmission line, wherein the bidirectional buffer comprises: an input differential amplifier section including two or more differential amplifiers, wherein a first differential amplifier generates positive polarity data signals from a difference between a positive polarity transmission line signal and a positive polarity transmitter signal, wherein a second differential amplifier generates negative polarity data signals from a difference between a negative polarity transmission line signal and a negative polarity transmitter signal, wherein common mode rejection is independently controlled in each of the first and second differential amplifiers using bias signals generated in response to an output common mode feedback voltage from the first and second differential amplifiers; and an output differential amplifier section that generates an output logic signal from the positive polarity data signals and the negative polarity data signals, wherein the output logic signal represents data received on the transmission line, wherein input noise is suppressed using an asymmetric transfer characteristic that offsets output signal logic levels with regard to input noise.