H02J 13/0075

Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network {for single frequency AC networks characterised by transmission structure between the control or monitoring unit and the controlled or monitored unit with direct transmission between the control or monitoring unit and the controlled or monitored unit using radio means}