A bioptical holographic laser scanning system employing a plurality of laser scanning stations about a holographic scanning disc having scanning facets with high and low elevation angle characteristics, as well as positive, negative and zero skew angle characteristics which strategically cooperate with groups of beam folding mirrors having optimized surface geometry characteristics. 0% by weight of polysaccharide, and aldehyde functionality content of at least of 0. A system is employed for variably actuating the intake and exhaust valves. The secondary circuit has a timing generating circuit generating timing signals for generating the transmit signals. The compliant pin enables the opto-electric module to be electrically coupled to the printed circuit board in a one-step process without exposing the opto-electric device to potentially damaging temperatures associated with soldering. The method includes one or more of the following: compiling statistical models of physical layers of a communications system; creating a priori distributions of cross-talk transfer functions; storing the models and the a priori distribution in a storage medium; and using the models and the a priori distributions to diagnose probable causes of events detected in said communications system.