This article deals with the problem of the mutual influence between software systems used in enterprise environment and enterprise integration processes. The position of CAD data and CAx systems in the integrated environment of manufacturing enterprises is clarified. As a consequence, the key role of CAx systems used in those companies is emphasized. It is noted that the integration of CAD data is nowadays only on a secondary level, via primarily integrated PDM systems. This limitation is a reason why we are developing a unified communication model focused on product-oriented data. Our approach is based on Internet technologies, so we believe that is independent enough. The proposed system of communication is based on a simple request-replay dialogue. The structure of this model is open and extensible, but we assume supervision supported by an Internet portal.