Patent ID: 8373686

Claim:
A multi-level point-to-point transmission system, comprising: at least one terminal resistor; a transmitter circuit, comprising: a first external resistor; and a transmitter, having a first reference terminal coupled to the first external resistor and at least one output terminal coupled to the terminal resistor, the transmitter generating a first reference current according to the first external resistor and determining a current flowing through the output terminal according to transmission data and the first reference current; and a receiver circuit, comprising: a second external resistor; a third external resistor; and at least one receiver, having a second reference terminal coupled to the second external resistor, a third reference terminal coupled to the third external resistor, and a receiving terminal coupled to the output terminal of the transmitter, the receiver generating a second reference current through the second external resistor and generating a reference voltage difference across the third external resistor according to the second reference current, the receiver judging a voltage at the receiving terminal according to the reference voltage difference so as to receive the transmission data correctly.