Patent ID: 6795493
Filing Date: 2004-09-21
Classification: H03K,H04L

Abstract:
A circuit for a transceiver output port of a local area networking device, said transceiver output port communicating with an unshielded twisted pair (UTP) cable, comprising:a first current source having a first terminal connected to ground and a second terminal connected to one terminal of a first resistor, the other terminal of said first resistor being connected to a supply voltage; a second current source having a first terminal connected to ground and a second terminal connected to one terminal of a second resistor, the other terminal of said second resistor being connected to the supply voltage; a third current source coupled between said first current source and said supply voltage; a fourth current source coupled between said second current source and said supply voltage; wherein the resistance values of said first resistor and said second resistor each are equal to Â½ that of the UTP cable for the purpose of impedance matching to the UTP cable, and said third and fourth current sources provide together an additional current which sustains a predetermined amplitude of a differential signal output from said circuit.