Apparatus for data communications between computers; apparatus for use in communications networks; cabinets adapted to hold communications apparatus; cable connectors for use in the data communications industry; communications electronics for computers; communications networks; communications programmes; communications systems; computer programs for use in communications; data communications apparatus; data communications hardware; data communications installations; data communications instruments; data communications receivers; data communications software; electronic data communications apparatus; electronic data communications installations; electronic message switching apparatus for use in communications installations; electronic telephone data communications apparatus; 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; installations for use in the networking of communications apparatus; microwave communications apparatus; microwave communications instruments; mobile data communications apparatus; modems for communications networks; optical communications installations; optical communications instruments; personal communications instruments; synchronous data communications apparatus; telephone communications apparatus; underwater communications devices; video communications apparatus; video communications instruments