Telecommunications apparatus and instruments; scientific, electronic and electrical apparatus and instruments; data processing and computing apparatus and input and output devices for use therewith; radio, radar, television, telegraphic, telephonic, testing, measuring and control apparatus and instruments; direction-finding and position-fixing apparatus; sound and vision recording and reproducing apparatus; electric signal recording and reproducing apparatus; apparatus and instruments for data transmission; nautical, navigational and surveying apparatus and instruments; infra-red sensing apparatus; electro-magnetic sensing apparatus