The emerge of technology systems in the result of interdependent dynamics of generation and diffusion of complementary bits of localised technological knowledge. Technological communication is the crucial element assessing the collective conditions under which technological knowledge is accumulated and diffused. The case study of the emerging Emilian technological system in the plastics sector shows that the synchronic and diachronic localised interactions among indusrial dynamics, institutional R&D efforts and technological interrelatedness are the deerminants of the systematic production, accumulation and distribution of localised technological knowledge, in turn explaining the origin and development of the technology system itself.