Access Control Systems
WHAT IS ACCESS CONTROL?
Controlling who can go where and when
Controlling passage in and out of areas
People, vehicles, or assets
Sorting out those that belong from those that don’t
Access Control
Proximity cards or key fob readers are often used to control access to a building or a specific area of a building. These devices read a key fob or ID card, and grant access only when the card sends an approved code. These code tables are stored on a network server that must be queried every time someone attempts to use an access card. When a card is swiped, the ID is transmitted to the server which either validates or rejects the code. Upon validation, the door is remotely opened, if the card is rejected the scanner will flash a no access code.
Proximity Reader
The proximity technology reader constantly transmits a low level fixed RF signal that provides energy to the card. When the card is held at a certain distance from the reader, the RF signal is absorbed by a small coil inside the card and powers the card's micro-chip which contains a unique identification code. Once powered, the card transmits the code to the reader. The whole process is completed in microseconds. The advantages of proximity over other technologies are numerous: no moving parts, no mechanical wear, no slots, no read heads to maintain. The reader can be concealed inside walls or special enclosures and, even when the reader is surface mounted, it has no openings to jam or tamper. The card is the most secure and practically impossible to duplicate. Cards can usually be read through a purse or wallet and through most other non-metallic materials. Card and reader orientation is not critical and keys or coins held in contact with the card will not alter its code or prevent accurate readings. Also, since proximity cards are less prone to physical damage or loss, there are great savings in reduced card replacement costs. Reading ranges depend primarily on the reader. The larger the reading range, the larger the reader's concealed antenna and hence, the size of the reader. A reader's read range is always specified using standard cards. If the card's coil is smaller, as in thin photo ID card, key fob or key tag type cards, the read range will be reduced by up to 40%. There is a great variety of proximity readers designed for different environments including vandal-resistant mullion mount, smaller decor style and integrated keypad/reader units. As the cost for Proximity technology goes down, expect even more users to select Proximity for all around maintenance free endurance.
Key Fob
The key fob is probably one of the best forms of access control. The key fob is made from a plastic device to hang on a key ring and contains the electronics in or on it.. The user holds it to the reader for access to a door. It is capable of reading and writing information to the system. This means the chip itself can be used to carry new information to a location rather than running wires throughout the building.. The chip can also be placed on a company ID badge for easy access to it. Its only disadvantage is the expense of the chips.
Strikes and Maglocks
Electric strikes or magnetic locks can be used to further regulate who passes through access points, providing an even greater level of protection.
Electric strikes are door locking devices, usually solenoid-operated, that will unlock the door when electrical power is applied to it. An opening that requires a person to be “buzzed in” is equipped with an electric strike. The buzzing sound is created when a button is pushed, sending an AC current through the device. This action disengages the device and allows the door to open. The operation just mentioned is a fail secure mode of operation, the most common function of an electric strike. A fail safe configuration will operate in the reverse condition; normally locked when power is applied and unlocked when power is interrupted. If desired, the buzzing sound can be eliminated by using a DC power source.
Magnetic locks are electromagnets that mount on the fixed frame and a strike plate that mounts on the moving door or gate. When the door closes, the strike plate automatically aligns with the magnet. The magnetic force then takes over, strongly securing the door. Release is achieved by switching of the power to the magnet. Magnetic locks are available in a range of holding forces.
Facilities that demand greater security, such as a detention facility, will need magnetic locks with holding forces that approach 2,000 pounds. Since electricity is required to power the magnet, all magnetic locks are fail safe unless they are equipped with a back-up power supply. Magnetic locks operate on DC power and, unlike electric strikes, are silent when locked or unlocked.
Both electric strikes and magnetic locks are commonly operated with a push-button switch, making them ideal for personnel-monitored openings such as office suites and hospital ward entrances. Be sure to check with the local code authority before applying magnetic locks to openings, as there are specific regulations governing their application.
While technically not a lock, automatic operators are an important component in an access control system. With the simple push of a button a door can be opened, held open to allow passage and then closed. Most buildings have at least one entrance that is required to be accessible in such a manner to meet ADA/accessibility codes. These entrances are not only for physically disabled persons, but for many situations when a person may not have their hands available to push or pull a door open.
