A permeable material compacting method includes feeding permeable material between at least one set of rollers, and decreasing a cross sectional area of the permeable material as it passes between the at least one set of rollers. The network coupling device couples the two data networks on the data link layer of the OSI reference model and is consequently transparent with respect to all the higher protocol layers. A remaining part of the starting material serves as body material for the other IGFET.