Digital optical transmission apparatus; Digital optical transmission instruments; Fibre optic apparatus; Fibre optic cable; Fibre optic connectors for telecommunications apparatus; Fibre optic couplings; Fibre optic instruments (not for medical purposes); Fibre optic link installations; Fibre optic terminals; Fibre optical elements; Fibre optics; Fibre optics communications apparatus for use with computer work stations; Fibre optics communications apparatus for use with electronic instruments; Fibre optics communications installations for use with computers; Fibre optics communications installations for use with electronic apparatus; Local optical fibre networks; Optical cables; Optical communication systems; Optical communications installations; Optical data transmission systems; Optical fibers (fibres) (light conducting filaments); Optical fibre apparatus, other than for medical use; Optical fibre installations; Optical fibre splicing apparatus; Optical fibre telecommunications apparatus; Optical fibres; Optical networks; Splice boxes for optical cables; Splice boxes for optical fibres; Splice connectors (optical)