An electrical node for forming daisy-chain buses with simultaneous serial data transmission and power transmission, comprising a) a first connector, which comprises first and second contacts for input transmission of power and a third contact for serial input data transmission of data; b) a second connector, which comprises first and second contacts for output transmission of power and a third contact for serial output data transmission of data, c) a third connector for a multipolar cable, which comprises first and second contacts (41, 42) for power supply to an electric/electronic point of use,; d) an electronic device which is adapted to read a frame from said third contact of said first connector characterized in that said first and second connector (2, 3) are suitable for a multipolar cable the serial data transmission in said first and second connector (2, 3) is unidirectional said first and second contacts of said first connector being electrically connected to said first and second contact of said second connector. said first and second contacts (41, 42) of said third connector being electrically connected to said first and second contacts of said second connector by a circuit that comprises an electrically operable switch said electronic device which is adapted to read a frame from said third contact of said first connector is in particular adapted to perform: d1) reading the value of a field containing first numerical information; d1) reading the value of a field containing second numerical information; and, when said first numerical information is equal to a predetermined value; d3) closing said switch for a time that is a function of the value of said second numerical information; and, when said first numerical information is different from the predetermined value; d4) increasing the value of said first numerical information contained in the field of said frame by a predetermined step and transmit the frame with the new value for the field toward said third contact of said second connector. a) a first connector, which comprises first and second contacts for input transmission of power and a third contact for serial input data transmission of data; b) a second connector, which comprises first and second contacts for output transmission of power and a third contact for serial output data transmission of data, c) a third connector for a multipolar cable, which comprises first and second contacts (41, 42) for power supply to an electric/electronic point of use,; d) an electronic device which is adapted to read a frame from said third contact of said first connector d1) reading the value of a field containing first numerical information; d1) reading the value of a field containing second numerical information; and, when said first numerical information is equal to a predetermined value; d3) closing said switch for a time that is a function of the value of said second numerical information; and, when said first numerical information is different from the predetermined value; d4) increasing the value of said first numerical information contained in the field of said frame by a predetermined step and transmit the frame with the new value for the field toward said third contact of said second connector.