A system for coupling a variety of circuit cards to a circuit board, each circuit card having a respective function, the system comprising: a sequence of connectors mounted on the circuit board, each connector in the sequence of connectors having a respective function; and, one or more connectors mounted on a circuit card for mating with respective ones of the sequence of connectors mounted on the circuit board to thereby couple the circuit card to the circuit board, the respective function of the circuit card determining which ones of the sequence of connectors mounted on the circuit board that the one or more connectors mounted on the circuit card mates with; whereby space on the circuit card opposite ones of the sequence of connectors mounted on the circuit board that the one or more connectors mounted on the circuit card do not mate with is available for mounting components.