Card Access System Basics
Electronic access system offers a better alternative as ID and authorization is programmable. An employee who leaves the firm can be denied access simply through programming the reader via the computer.
Similarly an employee who lost an ID card need not worry about someone gaining access using his card. The reader can be programmed to deny entry and even raise an alarm should that card be used.
The ability to log and keep track of who access a particular door and when it was accessed is a great advantage when it comes to investigating a security breach or theft.
More than that, companies are turing to card access system to keep track of their employees check in and check out time.
Coupled with Time and Attendance software, the card access system is fast replacing punch card system and freeing personnel from the mundane task of entering time sheet and calculating Overtime.
Components of a Card Access System
A basic Card Access System comprises the following:
- Controller - the brain of the system that checks if the data presented by the Reader is valid and whether access should be granted
- Reader - the interface at the door that reads either your Card, PIN number or Fingerprint
- Electronic Locks - used to lock the doors
Standalone Reader Controllers
A controller is the brain of the system and can operate independently of any computers. Seen another way, it is actually a dedicated-task computer with its own operating system and software. It communicates with the reader, compares the data read by the reader with the information stored at its memory, check its programming setting and output data to the lockset - to either lock or unlock the door, granting or denying access.
The HID EntryProx Reader is an example of a standalone reader controller. That is, the reader and the controller are not separated but one single unit. Such units are economical and very suitable for single door access control application where you only need to control a single door - namely the front door.
However if you want to continuously monitor who came in or out, or if you need regular reports done, standalone readers would not be appropriate as most of these units does not interfaced to a computer. It is designed to be completely standalone and any programming of new cards or deletion of cards are done via its keypad.
Unlike standalone reader controllers where reader and controller is combined in one single PCB board, networked controllers are separate and are normally housed in its own metal housing complete with power supply and back up batteries.
Network controllers can support up to 16 readers and are often placed in some central location. Where required, network controllers can be linked and connected to a computer and information is shared. Typical application would be companies that may be housed over several floors or over a large area and there are many entry and exit points.
Variety of Readers TechnologyThere is a wide range of readers and the associated technology; from the simple PIN keypad, to Card Readers, to the different range of biometric readers.
The most basic of all readers is the simple numeric keypad where a user need only to enter the correct 4 digit PIN to gain access. While this is convenient for the user, it is also the lowest form of security. Anyone who saw you enter your PIN would be able to gain access. Hence PIN only keypad is not recommended for exterior doors.
Magnetic strip card readers used to be popular (it is still being used - think of your ATM Card and Credit Cards) though it is fast being replaced by proximity cards. Behind the face of the card is a magnetic strip that allow data to be stored in magnetic fields. Unfortunately the data can be distorted when the card is subjected to strong magnetic field or to scratches, wear and tear over time.
The cost of proximity card have drastically reduced over the years, making it the most attractive alternative. With proximity card, there is no need to swipe the card, hence no wear and tear All that is needed is to flash the card at the reader and the data can be read.
What is gaining ground is the use of biometric, particularly fingerprints. Biometric readers can read and recognize the fingerprint pattern, increasing the security of the premises. Unlike the card system, it is not possible to pass your fingerprints to someone else. And with the newer batch of fingerprint biometric reader, it can differentiate "live" fingerprints from "dead " fingerprints.
How Proximity Work
Convenience is desirable and what is easier than approaching a door, opening it and walking in, just as if it were unlocked? With proximity cards, such ease of ingress can be achieved without compromising security. A credit card-sized card can be kept in a wallet, briefcase or purse and when a person walks within three feet of a door, a reader will recognize the card and unlock the door.
Embedded in every proximity card is a special circuitry where its ID number is encoded and an antennae that is used to transmit data using radio frequency.
There are two types of proximity cards: active or passive. Active proximity cards are typically larger and thicker and contain a battery that powers the embedded circuitry. Passive cards do not have its own power source. It draws its power from the reader when it comes within its proximity.
Active cards are typically used for application where the reader must read the card from a longer distance such as cars entering a car park. Passive cards are typically used for access in and out of offices and building.
Proximity readers use an antenna that transmits RF, usually low frequency RF. When an access card enters the the RF field, it transmits a signal back to the reader, which then decodes the signal and grants or denies access.
How Fingerprint Biometrics Work
Fingerprints are unique and no two persons have similar fingerprint. For that matter, no two fingers have similar prints.
A fingerprint scanner system has two basic jobs -- it needs to get an image of your finger, and it needs to determine whether the pattern of ridges and valleys in this image matches the pattern of ridges and valleys in pre-scanned images.
There are a number of different ways to get an image of somebody's finger. The most common methods today are optical scanning. The heart of an optical scanner is a charge coupled device (CCD), the same light sensor system used in cameras. A CCD is basically an array of light-sensitive diodes which generate an electrical signal in response to light.
The scanning process starts when you place your finger on a glass plate, and a CCD camera takes a picture. The scanner has its own light source to illuminate the ridges of the finger. The CCD system actually generates an image is released.