A method, computer software program, and system provides automatic selection of time slots in time-division multiplexed connections. A primary controller node is dynamically designated to perform the time slot assignments. Other embodiments are described and claimed. A method for preventing the back conversion is also disclosed. A third engine, responsive to the attenuation component and the relative permittivity parameter, performs a least squares analysis to determine a loss tangent parameter associated with the substrate over the specified frequency range.