System for transmission line termination by signal cancellation

Abstract

A communication system having first and second states for use with a shared transmission line composed of at least two conductors and composed of first and second transmission line segments connected to each other at a single connection point. In the first state, a termination is coupled to the single connection point and is operative to at least attenuate a signal propagated between the first and second segments. In the second state, a driver is coupled to the connection point and is operative to conduct a signal over the first and second segments.

What is claimed is: 
     
         1 . A device for use with a wire pair in walls of a building and connected to an outlet, the wire pair being connected in a bus topology for carrying a digital data signal, said device comprising:
 a connector for connecting to the outlet for coupling to the digital data signal carried over the wire pair; and   a termination circuit selectively couplable to said connector and constructed for terminating the digital data signal propagated over the wire pair when said device is connected to said connector,   wherein said device is switchable between a first state in which said termination circuit is coupled to said connector and a second state in which said termination circuit is not coupled to said connector.