Install the long cable through your house as needed. One end must be near a wall socket, the other at the Ronja console. Strip all ends of the cable. Solder four 1-inch 4mm^2 hard wire pieces to all conductors of the cable on both side. Insulate the joints with duct tape.
Insert the ends near the wall socket into the wire nut and tighten. Leave the 1-meter piece of wire at the console for future interconnection of the heating between RX and TX (in series).