1. A distributed control comprising: a master controller connected to a transmission line and adapted to deliver power and data to the transmission line and to receive data from the transmission line; said transmission line comprised of first and second conductors configured to carry differential data; and a plurality of couplers arranged along the transmission line, each coupler enclosing a pair of inductive coupling loops formed in said transmission line, and passing through a coil to thereby establish mutual coupling between the transmission line and the coil, said coil connected to one or more slave; wherein said mutual coupling permits data transfer from the master controller to the one or more slave controllers and from the one or more slave controllers to the master controller.