CANTON, Mass., Dec. 29 -- Robotic Vision Systems Inc. reported that Pratt & Whitney has adopted RVSI's Data Matrix two-dimensional symbology for on-parts marking of Pratt & Whitney engines. In addition, RVSI announced that the engine manufacturer would use RVSI's MXi hand-held imager -- co-developed with Polaroid Corp. -- to read the parts.Data Matrix codes, which resemble small checkerboards, can encode more alphanumeric information than one-dimensional bar codes. Data Matrix codes may be marked directly on a product using such methods as chemical etching, dot peening, ink jet, laser marking or lithography.