A signalling system is provided which comprises first and second signalling devices. The first signalling device comprises (i) a plurality of light emitters each for emitting a respective light beam carrying information; and (ii) a lens system for collecting light emitted from the plurality of light emitters and for directing the light beams in respective directions within the field of view of the lens system. The second signalling device comprises (i) a lens system for collecting light emitted from a light emitter of the first signalling device; (ii) a light detector for receiving the collected light from the lens system and for converting the received light into corresponding electrical signals; and (iii) means for processing the electrical signals from the light detector to retrieve the information.