The article explores alternative sign systems in a communicative framework. From this intersemiotic perspective, the author explores the conversion of signs between different semiotic forms of representation particularly in relation to objects and concepts. Stressing the importance of both linguistic and non-linguistic signs, as well as their interactions and potential interchangeabilitiy in LSP text, the author argues that adequate specialist knowledge is a pre-conditions for the successful conversion of signs, at least from a communicative perspective.