The ÖVE/ÖNORM EN 61970-404 High Speed Data Access (HSDA) specification specifies a generalized interface for efficient exchange of data. The specification takes into account the latencies caused by a Local Area Network (LAN) providing efficient data exchange also over Local Area Networks. ÖVE/ÖNORM EN 61970-404 is derived from the Object Management Group (OMG) Data Acquisition from Industrial Systems section Data Access (DAIS DA) specification. OMG DAIS DA relies on the OMG Data Access Facility (DAF) and OPC Data Access (DA) specifications. OMG DAIS DA is a Platform Specific Model (PSM) with CORBA as the platform and OPC DA is a PSM with Microsoft COM as the platform. ÖVE/ÖNORM EN 61970-404 describes the functionality of these PSMs in a technology independent way (i.e., as a Platform Independent Model (PIM)). Hence it explains the functionality to a level that can be used to create additional PSMs or act as an introduction to existing PSMs, i.e. DAIS DA and OPC DA. Implementers wanting an introduction to OMG DAIS DA and OPC DA shall read these documents.