A module carrier unit comprises a plurality of passenger interface modules that perform different functions, the functions including at least one of inputting and outputting information, the modules having a common size, shape, and interface; an outer case portion comprising a plurality of receptacles, each having a common size, shape, and interface designed to receive one of the modules, the plurality of receptacles being such that a first module having a first function is operable in a first receptacle, and a second module having a second function is operable in the first receptacle, the modules being removably connected to the receptacles; and a communications interface that performs at least one of transmitting and receiving data to and from a processor located near a seat of a passenger in the vehicle.