A linear motor for which armature core can readily be manufactured is provided. The second set of spherically-shaped microlenses are located in the areas between individual microlenses of the first set in such a way that there is minimized gapping over the entire microlens array. The device also includes a summer component where the signals summed include at least the first upstream sum audio signal. This cell assembly is readily amendable to automated wafer plating. The message data payload is uniquely identifiable within a universe of pre-defined message data payloads so that the information enables the test engine to construct the well formed message.