Access control has traditionally been done by running wires to points such as doors, gates, turnstiles, etc. and then having electronic keys such as cards or electronic fobs to open. Control includes personal access rights, time of day or week and specific location.
As the need develops for expansion or renovation, wires can be added or changed.
But now technology has developed to perform these same functions with a wireless system and at the same cost as wires! So new or expansion needs can be met within a comparable cost and can be integrated with what is already on site. The added advantage of wireless systems is faster modification to access rights and the ability to replace cards and card readers with smart phone scanning. No more lost card replacement or recoding of access rights on cards.