COM is the Component Object Model. This is a standard Microsoft interface used in inter-process communications within a computer. When applications on two different computers use this method it is called DCOM, or the Distributed Component Object Model COM is a communication protocol that allows one program to initiate a communication link that another program can respond. It allows a program to request info.
COM and DCOM in ThinManager
ThinManager makes a COM connection (or DCOM on a remote computer) to make changes to the configuration database maintained by ThinServer.
ThinServer makes a COM connection (or DCOM on a remote computer) to update status information (icon colors, etc.) in the ThinManager interface.
ThinServer will make a COM connection (or DCOM on a remote machine) to the WTSAPI32.dll on the terminal servers to pull session data to configure SmartSession.
ThinServer will make a COM connection (or DCOM on a remote box) to the WMI on the terminal servers to pull process data to configure SmartSession.