Backbone bus card

The electronics in the satellite are designed as a modular system. Each of the subsystems is produced on modular circuit board interconnected with each other with a backbone bus card. The backbone bus card holds the various intersystem communication buses as well as the subsystem power buses.
The modular system design was choosen instead of the stacked (104-pin) design which is more common in the cubesat community, because it simplifies the debug and integration work. 

                                    The Backbone Bus Card