A utility pole that supports the wires for two or more companies. A typical joint pole has three types of wires: electric power, cable television, and telephone. In other locations, they support such devices as signs, traffic signals, street lights, and fire and police call boxes.
Working up, on one such pole, you have: Telephone cable, cable television cable, some unused space, and a stepdown transformer. A stepdown transformer is used for converting primary voltage to secondary voltage.