A method and an apparatus for multitone modulation to transmit at least two packets of data, each comprising a plurality of symbols, to provide inter-packet interleaving. The diffuser selects a specific error diffusion matrix for each selected pixel data according to the nozzle information, and diffuses the error to the pixel data not subjected to the conversion. The tablet is completely coated with a film of polymeric material insoluble in water andor in aqueous fluids, on which one or more incisions delimiting an area of exactly calculated geometric shape and size, have been made through the use of a laser beam of appropriate power and intensity. The crash data is correlated based upon a vehicle type parameter.