ABSTRACT
The objective of physical access control is not to restrict access but to control it. That is, the data center manager should know who is granted access, when access is granted, and why. This chapter provides overview of the function of access control systems, the physical elements they can use, and the basic techniques they employ. It also describes two popular access control technologies, keypad access control and portable-key access control, and discusses their advantages and disadvantages. The chapter also examines two other technologies, proximity access control and physical-attribute access control, as well as several developing technologies.
