Electrical and software: The circuitry that interconnects and provides compatibility between a computer and an operator, support device (e.g., timer, DAC) or communications medium (e.g., serial interface) in a computer system. The electrical interface may be physical (involving a connector) or logical (involving software). It also means a circuitry or software that interconnects and provides compatibility between a computer and an operator (user interface) or peripheral device (communications interface). Mechanical: The physical mating surfaces of two components or subsystems.