Plug-ins

Plug-ins connect to the system using the EPOC Component Object Model (ECom). ECom is based on client/server architecture and provides services to instantiate, resolve, and destroy instances of plug-ins at run time. For more information, see the ECom architecture.

A hostile or malfunctioning plug-in may cause crashes or security leaks, even on otherwise well-tested applications. The platform security architecture protects the processes by verifying that the plug-in has equal or greater set of capabilities than the process in which it is loaded. For more information, see the ECom and the platform security capability model.

Communication plug-ins +

It is possible to use plug-ins to implement additional functionality to serial, socket, and messaging frameworks. These plug-ins are especially important for security because they deal with communication.

For serial communication there are serial protocol modules (CSY modules ), which are loaded by the Serial Comms Server. For more information on serial communication, see Using Serial Communications Server Client-Side.
For socket-based communication there are protocol modules (PRT), which are loaded by the Socket Server. For more information on socket-based communication, see Using Socket Server.
For messaging there are Message Type Modules (MTM), which include both client and server components. MTMs are a set of dlls rather than a single dll. For more information, see Message Type Modules.