GE D20 M+SS Versatile Substation SontrollerDescription Type: Substation Controller Series: GE Digital Energy Features Modular Design: The D20 main chassis comes in three distinct types to accommodate various size and communication requirements. Data Processing: The D20ME II CPU Board manages data collection and delivery to host computers, executes local automation algorithms, and maintains I O and device data within the system database. Communication Ports: Equipped with multiple RS 232 485