Through the use of a variable state length initialization, both the transmitter and the receiver can have control of the length of one or more initialization states. The method, based in the frequency domain, uses the concept of linear independence of two equationstwo unknowns to arrive at the secondary path estimate. A drive unit drives the display panel in response to an input image signal. The third and fourth jack contacts are configured to carry a second differential signal. In one embodiment, the blades of one set form a right angle with the blades of any set next to it. The drain grate system can open in response to a high flow rate to allow liquid and debris to flow into the drain.