A hydrophobic ABS plastics material is formed from an acrylonitrile-butadiene-styrene copolymer plastic feed stock and a silicone additive. The inventive composition exhibits low smoke generation. The acousto-optic cell is sequentially driven by RF voltages at two or more frequencies. In this process data vectors are considered similar, for example, if the corresponding instances of a predictive distribution, conditioned with the variable value assignments found in the data vectors, are similar. In one preferred embodiment, the radio unit is DDCRU.