Electronic apparatus for developing communication links; Electronic apparatus for providing communication links; Electronic apparatus for testing communication links; Electronic communication apparatus; Apparatus for controlling lighting; Apparatus for lighting control; Computer controllers for operating lighting apparatus; Computer controls for lighting apparatus; Computer controls for lighting instruments; Apparatus for use in security control; Electric controlled access security apparatus; Electronic controlled access security apparatus; Electronic tags for security control purposes; Automatic access control systems; Automatic access control apparatus; Electric apparatus for use in parking control; Electrical control apparatus for automatic gates for car parks; Electronic apparatus for the control of car parking; Electronic instruments for controlling systems associated with buildings; Electronic instruments for controlling systems in buildings; Remote entry control apparatus for buildings; Instruments for temperature control; Sensing devices for the control of temperatures (other than for medical use); Temperature compensation controls; Analogue control apparatus; Analogue displays; Apparatus for creating digital effects; Apparatus for personnel entry control; Apparatus for the monitoring of personnel; Electrical apparatus for the locating of personnel; Electrical apparatus for the paging of personnel