OPC Data Client is a name for the product as a whole. It can be used from various languages and environments.

Parts of the product can be differentiated by the kind of OPC specifications they deal with. OPC Data Client-Classic refers to parts of the product that deal with "Classic" OPC specifications, based on COM/DCOM (or OPC XML). It can be used from COM tools or from .NET. Similarly, the OPC Data Client-UA referts to parts of the product that deal with OPC Unified Architecture (OPC UA) specifications, and it also supports both .NET and COM development targets.

The other way to differentiate the parts of the product is by the principal development technology they are aiming at: Either Microsoft .NET, or Microsoft .COM (so-called OLE Automation). When we need such disctinction, we refer to there product parts as OPC Data Client.NET or OPC Data Client-COM, respectively. When necessary, the differing text is marked with corresponding COM or .NET icon.

The following table explains the product part names, and how they relate to OPC specifications they cover, and to the development tools platform that can be used with them.

Development Tools/Target Platform:		Microsoft .NET and Python	Microsoft COM
OPC Specifications
OPC “Classic” (DCOM based)	OPC Data Access (OPC-DA)	OPC Data Client-Classic OPC Data Client.NET	OPC Data Client-Classic OPC Data Client-COM
	OPC Alarms and Events (OPC-A&E)
OPC XML-DA (XML Data Access)
OPC Unified Architecture (OPC-UA), for Data Access, Alarms & Conditions		OPC Data Client-UA OPC Data Client.NET	OPC Data Client-UA OPC Data Client-COM
OPC UA PubSub		OPC Data Client-UA OPC Data Client.NET	OPC Data Client-UA OPC Data Client-COM

The OPC XML-DA support in OPC Data Client.NET is transparently integrated into the component. Wherever this document refers to “OPC Data Access”, it also usually applies to OPC XML-DA.

All products/product parts are delivered in a single installation package.

The main component of OPC Data Client is called EasyOPC, and it allows programmatic client access to OPC servers, Other parts of OPC Data Client are user interface objects (dialogs and controls), extensions, tools, and so on.