The 2500C-R4 Base provides slots for a Power Supply and Remote Base Controller (RBC), and 4 I/O slots for Compact IO modules.  The chassis design allows for subpanel mounting.

The backplane provides power to all the modules and communications between the RBC and I/O slots.  In addition it provides a high-speed data exchange bus which supports all the Compact System’s advanced modules and coprocessor modules.  The high-speed data bus includes the RBC and all 4 I/O slots, and is integrated into the connector on each slot.