The invention relates to a communications method of communicating states from an activation unit to a receiver via a communications bus, wherein the state may be activation/deactivation of an activation unit, and wherein the state is communicated to the receiver via a serial data stream timed by a clock signal, said data stream transmitting data packets which comprise an identification part and a data pare wherein: ● the identification part comprises a plurality of bits which identify which activation units the data packet concerns, and ● the data part comprises a plurality of bits which individually identify the state of an activation unit. The invention also relates to a system based on the communications method and comprising an activation unit and a receiver. In addition, the invention relates to an activation unit and a receiver.
