The ÖVE/ÖNORM EN 61970-407 Time Series Data Access (TSDA) 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 61970-407 is derived from the Object Management Group (OMG) Historical Data Access from Industrial Systems (HDAIS) specification. OMG HDAIS relies on the OMG Data Access Facility (DAF) and OPC Historical Data Access (HDA) specifications. OMG HDAIS is a Platform Specific Model (PSM) with CORBA as the platform and OPC HDA is a PSM with Microsoft COM as the platform. The ÖVE/ÖNORM EN 61970-407 specification 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 be an introduction to existing PSMs, i.e. HDAIS and OPC HDA. Implementers wanting an introduction to OMG HDAIS and OPC HDA should read these documents.