Electronic blackboards; electronic interactive whiteboards; electronic computer whiteboards; electronic tablet computers for note-taking; microphones; apparatus for the recording, transmission and reproduction of sound and images; digital signage display panels; digital signage monitors; digital signage; TV monitors; television receivers; wireless television sets for providing video conferencing and telephone service over the internet; LED displays; LED signs; USB transmitters for PC screen sharing to signage, TV, LED display sets; display monitors with built-in cameras and microphones; computers; computer display monitors; computer application software; computer software for allowing sharing and mirroring contents between laptops, mobile devices, etc. and displays; computer software for video conferencing; computer hardware and recorded software sold as a unit for use with digital signage monitoring equipment, for receiving, processing, transmitting and displaying data and images; electronic pens; touch screens; multi touch screens; computer software to be embedded on an electronic blackboard; computer application (app) to be used when users write the contents on an electronic blackboard; computer application (app) allowing to share the contents written on an electronic blackboard.