OPC is a common, high performance communication interface based on DCOM and Web Services technology that enables automation/control applications running on your PC to communicate with control equipment. In short, the OPC specification defines a set of interfaces for easy-to-use objects, and includes the functions and properties to enable the manipulation of these objects.
The VTS OPC Server allows VTS to act as a server to an OPC client. This allows other programs (including another VTS application with an OPC client driver) to exchange data with your VTS application.