Logic circuitry is powered by a partially rectified alternating current waveform. The system includes a first digital-to-analog converter to convert a digital signal into a corresponding first analog signal. The method comprises first creating a graphical program, wherein the graphical program may implement a measurement function. In the control plane view, transmission facilities are represented as logical links forming a topology that can be used for the purpose of routing the VPN. The insertion channel is inclined at an angle of between 30 and 60 degrees relative to a horizontal plane.