Abstract: Communication apparatus for communicating data between a processor on board a vehicle and a display for a user of the vehicle is disclosed. The apparatus includes a first light source operable to generate a modulated output representative of the data, a first receiver for receiving the modulated output of the first light source; and a communication device for communication between the receiver and the display. The first receiver is mounted on a suit worn by the user in operation of the vehicle. The communication apparatus is expected to be applicable, for example, with head-mounted displays used by pilots of aircraft.