Component Object Model, or COM technologies in the Microsoft Windows
family of operating systems enables software components to communicate.  
Developers use COM to create re-usable software modules that are
exposed within the Windows environment.  Modules from different
applications can be integrated into seamless and powerful solutions.

Distributed Component Object Model, or DCOM is part of the Microsoft COM
family of technologies.  Developers use DCOM to expose software modules
across networks to build efficient distributed applications.

Control Products Unlimited, Inc. uses COM in several of our applications and
solutions.  For example, COM is used by
OPClient to share process
information with field instrumentation through
OPC.  DBReport uses COM to
communicate with Microsoft Excel for historical reporting and trending
features.  The
RTDB uses DCOM to expose process data to client
applications across the network.