System selectors put one display or speaker system in front of several possible sources: AV matrix and switcher boxes that route video and audio from multiple inputs to one or more outputs, and the simpler selector switches that let a presenter pick between a laptop, a media player, or another source with one button. Any shared room with more than one thing that might need to go on screen relies on a selector to sort it out.
Size the selector by inputs and outputs, not just by the room in front of it today - matrix switchers should have headroom for sources the room will add later, since retrofitting a larger switcher is far more disruptive than sizing correctly the first time. Confirm the selector supports the video and audio formats and resolutions the sources and displays actually use; a mismatch here is a common cause of no-signal complaints. For rooms with a control system, choose a selector the controller can command directly. COLAMCO quotes AV switching and selection hardware with the displays and sources it connects for business, government, and education facilities.