The heating is a subsystem of Ronja devices which keeps the lenses thermally permanently somewhat above the air and thus prevents condenation, moisture, mist and ice buildup on the lens and obscuration of the optical path. With heating, Ronja fails only during a very dense fog. Without heating, Ronja would fail during some rains and during mist and fog (usually in the morning and evening).
The heating includes long run of cable through the house.
The heating is plugged into normal wall outlet. The other end provides two wires that are to be installed into wire nuts in the optical heads and the remaining heating leads (one from RX and one from TX) interconnected with heating interconnect cable.