A system and method of supplying conditioned air to an aircraft environmental control system during ground support operations that uses at least one flow control door to control the flow of cooling air through a heat exchanger. The controller selects one of the clock inputs to avoid having a high-level spur in an output of the DDS filter. A thin strip of adhesive is placed between the two materials at the seam line. Common code segments in the dump may be automatically identified. The first and second parts are movable away from one another and the receiver is removably attached to the item.