Industrial automation systems and integration product data representation and exchange part 21 implementation methods clear text encoding of the exchange structure. Industrial automation systems and integration product data representation and exchange part 21 implementation methods clear text encoding of the exchange structure this part of iso 10303 specifies an exchange structure format using a clear text encoding of product data for which the conceptual model is specified in the express language . Industrial automation systems and integration product data representation and exchange part 21 implementation methods clear text encoding of the exchange structure abstract specifies an exchange structure format using a clear text encoding of product data for which the conceptual model is specified in the express language. Industrial automation systems and integration product data representation and exchange part 21 implementation methods clear text encoding of the exchange structure technical corrigendum 1. Iso 10303 211994 industrial automation systems and integration product data representation and exchange part 21 implementation methods clear text encoding of the exchange structure specifies an exchange structure format using a clear text encoding of product data for which the conceptual model is specified in the express language the