Wikipedia
Source: EUROCONTROL SDDS Website
RMCDE (SuRveillance Message Conversion and Distribution Equipment) is the name of a system designed to distribute the surveillance information to a community of user systems.
A user of surveillance data in a general sense is defined in this context as any Air Traffic Control (ATC) subsystem having a requirement to receive at defined instants the best and most up-to-date position information for all air traffic of interest to this user (e.g. Operator Display System, Flight Data Processing System, ATC Tools, Flow-Control Management Units, Remote Terminal Maneuvering Area's, Military Units, etc.). The data can be originating from a surveillance sensor (e.g. radar, ADS-B receiver, Multi-lateration system) or a surveillance data processing system (e.g. ARTAS)
RMCDE is a Multibus II based multiprocessor system composed of a number of subsystems (processor and IO boards) connected through a parallel data bus.
In addition to its distribution function, the RMCDE offers additional capabilities to manage the surveillance data flow like data validation, conversion and filtering.