Abstract: The software reconfigurable transmission line apparatus uses a multi layer printed circuit board on which is deposited a plurality of signal conductors and associated ground plane conductors. The signal conductors and ground plane conductors are oriented in a parallel juxtaposed configuration such that they implement a two wire shielded transmission line. Switching devices located at either end of each of these conductors are operable under software control to reconfigure the connection of these conductors to their associated terminals to implement two wire floating or coax transmission lines.