A computer system (200) includes a baseboard (202) having a first side (201) and a second side (203), where the first side and the second side define a first key opening (205) and a second key opening (207). A mezzanine card interface (208) is coupled to the baseboard. A keying mechanism (219) is coupled to interface with the baseboard through the first key opening, where coupling the keying mechanism to the baseboard initiates a first key signal (225), and where the first key signal operates a logic circuit (229) to permit a first operating voltage (218) to power the mezzanine card interface. Alternatively, the keying mechanism can be coupled to interface with the baseboard through the second key opening, where coupling the keying mechanism to the baseboard initiates a second key signal (227), and where the second key signal operates the logic circuit to permit a second operating voltage (220) to power the mezzanine card interface. This configuration mechanism is repeated for any other mezzanine card interfaces on the baseboard. The logic circuit (229) disallows the application of operating voltages to the mezzanine card interfaces if the configurations are not compatible with the architecture of the baseboard. In the event of incompatible configurations, the logic circuit also communicates a configuration failure signal to the operator or system manager.