The cable is connected to the landing gear toot on both sides. A second cable goes from this hook to the towing winch under the fuselage. The cable forms a loop that is connected to the device.

The winch is moved (retracted?) by a mechanism moved by a small four blades propeller.

Seems that the towing cable passes through the rectangular opening into the fuselage to the pulley on the back.

Below: the tail is protected from the towing cable by two oblique cable wires.

A small propeller (electric generator?) is installed on the right lower wing.

Right: connecting a pulley.

It's not clear if all these photos are relative to the same kind of towing device, or alternative ones.