An apparatus comprising: a cable having an electrical conductor spanning the length of the cable; a pod comprising at least two coils (212, 214) and a controller, characterized in that the pod further comprises a magnetic core (222,232), wherein: the pod is configured around the outside of the cable such that the magnetic core (222, 232) is around and inductively coupled to the electrical conductor of the cable, wherein the magnetic core is not galvanically connected to the electrical conductor of the cable, the at least two coils (212, 214) being inductively coupled to the magnetic core (222, 232), and the controller being connected to the at least two coils (212, 214); the pod is configured to transmit one or more outgoing electrical signals on the electrical conductor of the cable by the controller electrically energizing a transmitter coil of the at least two coils (212, 214) such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more outgoing electrical signals are induced in the electrical conductor of the cable; the pod is configured to repeat one or more incoming electrical signals on the electrical conductor of the cable by the one or more incoming electrical signals inducing incoming magnetic energy in the magnetic core (232, 222) such that incoming electrical energy is induced in a receiver coil of the at least two coils (212, 214), wherein the controller is configured to respond to the incoming electrical energy by electrically energizing the transmitter coil such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more incoming electrical signals are inductively repeated in the electrical conductor of the cable, wherein the transmitter coil and the receiver coil are two different coils. a cable having an electrical conductor spanning the length of the cable; a pod comprising at least two coils (212, 214) and a controller, characterized in that the pod further comprises a magnetic core (222,232), wherein: the pod is configured around the outside of the cable such that the magnetic core (222, 232) is around and inductively coupled to the electrical conductor of the cable, wherein the magnetic core is not galvanically connected to the electrical conductor of the cable, the at least two coils (212, 214) being inductively coupled to the magnetic core (222, 232), and the controller being connected to the at least two coils (212, 214); the pod is configured to transmit one or more outgoing electrical signals on the electrical conductor of the cable by the controller electrically energizing a transmitter coil of the at least two coils (212, 214) such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more outgoing electrical signals are induced in the electrical conductor of the cable; the pod is configured to repeat one or more incoming electrical signals on the electrical conductor of the cable by the one or more incoming electrical signals inducing incoming magnetic energy in the magnetic core (232, 222) such that incoming electrical energy is induced in a receiver coil of the at least two coils (212, 214), wherein the controller is configured to respond to the incoming electrical energy by electrically energizing the transmitter coil such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more incoming electrical signals are inductively repeated in the electrical conductor of the cable, the pod is configured around the outside of the cable such that the magnetic core (222, 232) is around and inductively coupled to the electrical conductor of the cable, wherein the magnetic core is not galvanically connected to the electrical conductor of the cable, the at least two coils (212, 214) being inductively coupled to the magnetic core (222, 232), and the controller being connected to the at least two coils (212, 214); the pod is configured to transmit one or more outgoing electrical signals on the electrical conductor of the cable by the controller electrically energizing a transmitter coil of the at least two coils (212, 214) such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more outgoing electrical signals are induced in the electrical conductor of the cable; the pod is configured to repeat one or more incoming electrical signals on the electrical conductor of the cable by the one or more incoming electrical signals inducing incoming magnetic energy in the magnetic core (232, 222) such that incoming electrical energy is induced in a receiver coil of the at least two coils (212, 214), wherein the controller is configured to respond to the incoming electrical energy by electrically energizing the transmitter coil such that outgoing magnetic energy is induced in the magnetic core (232, 222) such that the one or more incoming electrical signals are inductively repeated in the electrical conductor of the cable,