Patent ID: 6448901
Filing Date: 2002-09-10
Classification: H04L

Abstract:
A system having a plurality of nodes for communicating with each other, said system including a power conductor for providing power to a power terminal of each node, a data conductor for carrying data to and from a data terminal of each node, and a common conductor, wherein the system includes at least one pull-up resistor connected between the power conductor and the data conductor, and wherein each of a plurality of said nodes includes an interface circuit comprising:a) an isolation element having a first terminal connected to the data terminal, and a second terminal; b) a switch for connecting the isolation element's second terminal to the common conductor responsive to a first level of a local data signal and for disconnecting the isolation element's second terminal responsive to a second. level of the local data signal; and c) an indicator element connected between the power conductor and the isolation element's second terminal, said indicator element including a preselected impedance, and said indicator element providing a human perceptible indication while the switch is closed.