The two methods of using the natural gas pipeline as a communication medium are presented. In the first method, the pipeline is treated as a microwave waveguide. In the second method, the pipe is treated as a leaky feeder or a multi-ground neutral and the signal is directly injected onto the metal pipe. These methods are tested on existing pipeline loops at UMR and Batelle and the results are presented, demonstrating the feasibility of both methods. The need to develop secure system monitoring and control techniques between the field and control centers and to robotic devices in the pipeline is discussed.