Patent ID: 8068537

Claim:
A communication circuit for providing a bi-directional data transmission over a signal line, the communication circuit being adapted for receiving a first digital data stream and for transmitting a corresponding first signal into a near end of a signal line to be transmitted to a remote device, the remote device being connected to a far end of the signal line, the communication circuit being adapted for receiving a second signal at the near end of the signal line from the remote device and for deriving a second digital data stream from this signal, the communication circuit comprising: a signal generator adapted for providing a first driver signal at a first generator output and a second driver signal at a second generator output, each in response to the first digital data stream; an interface circuit adapted for providing, in response to the first driver signal and the second driver signal, the first signal to be transmitted to the near end of the signal line, wherein the interface circuit comprises a first terminal connected to the signal generator for receiving the first driver signal, an output connected to the near end of the signal line, and a second terminal connected to the signal driver for receiving the second driver signal, wherein the second terminal is further connected to an input of the extraction circuit; and an extraction circuit adapted for detecting the second digital data stream, in response to a comparator signal deduced from the near end of the signal line and the second driver signal; wherein the signal generator comprises, a first driver adapted for generating at an output a first high voltage or a first low voltage depending on an actual bit value of the first digital data stream, wherein the output of the first driver is connected by a first resistor to the first terminal of the interface circuit, and a second driver adapted for generating at an output a second high voltage or a second low voltage depending on an inverted actual bit value of the first digital data stream, wherein the output of the second driver is connected by a second resistor to the second terminal of the interface circuit; the communication circuit further comprising a complementary interface circuit with a complementary resistance with respect to a complementary first terminal and a complementary second terminal, wherein the first complementary terminal is connected to a complementary transmission line and by a complementary first resistor to the output of the second driver, wherein the second complementary terminal is connected to a second input of the voltage comparator, and by a complementary second resistor to the output of the first driver, and wherein the voltage comparator generates the second digital data stream in response to the course of the voltage difference between the second terminal and the second complementary terminal.