The most typical use of OPC Data Client-COM or OPC Data Client-UA for COM involves a thick-client user application written in a tool or language that supports COM automation. This application uses the types from OPC Data Client-COM (or OPC Data Client-UA for COM) object model, and accesses data within OPC servers that are located on remote computers on the same LAN (Local Area Network). The communication with the target OPC server is performed by Microsoft COM/DCOM technology.

The following picture shows how the individual pieces work together: