Some embodiments describe a DC meter system that can be placed in-line between a power source and an electrical load. In some embodiments, the DC meter system includes a DC meter that has multiple inputs for receiving electricity from multiple power sources. In some embodiments, the DC meter has one or more outputs, each capable of delivering electricity to a different electrical load. In some embodiments, the DC meter can combine electricity from two or more of the multiple inputs into one of the outputs. In some embodiments, the DC meter has a controller that can enable a user to deliver electricity from a particular input to a particular output. In some embodiments, the DC meter is configured to enable transition of electricity between an input and an output in a bi-directional manner. In some embodiments, the DC meter can record an amount of electricity transmitted in either direction.

Electricity meter, arranged to measure electrical energy supplied to an installation by a distribution network comprising a plurality of phases, the electricity meter including a communication module arranged to implement a communication by power-line communication; a switching circuit arranged to selectively connect the communication module to one of the phases; a processing unit arranged to control the switching circuit so as to connect the communication module to an optimised phase, from among the phases, which is selected dynamically to optimise a quality of the communication by power-line communication.

A transmission method for transmitting a fragment of an IP packet from a first node device to a third node device through a second node device. The first and second node devices are configured for communicating by powerline and by radio frequency. The second and third node devices can communicate only using a single communication medium from powerline and radio frequency. A first fragment sent by said first node device either by powerline or by radio frequency is received. An acknowledgement message is sent by to said first node device using a second communication medium selected from powerline and radio frequency so that it is different from said single medium. Then said first fragment is transmitted to said third node device using said single communication medium.

A transmission method for transmitting a packet from a first node device to a second node device of an electrical supply network, the transmission method includes the following steps performed by the first node device: transmitting the IP packet by radio frequency in the case where a level of use by the first node device of the transmission by radio frequency calculated on a sliding time window with respect to a maximum use time is below a first threshold, the first threshold being below a second threshold beyond which any transmission by radio frequency is interrupted; transmitting the IP packet by powerline otherwise, and, in the case where the powerline transmission fails, transmitting the IP packet by radio frequency in the case where the level of use is below the second threshold.