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Introduction to Electronic Access Control

An Overview of the Technology with Tips on Choosing the System You Need


How Does an EAC System Work?

In its simplest form, an EAC system consists of an electronic door lock, a reader (such as a card reader), and some form of electronic controller. Almost everyone has had the experience of being "buzzed in" to a controlled area. The process goes something like this: After recognizing your face, a receptionist presses a button and you hear a buzzing sound telling you that door is now open. (The "buzzing" sound you hear is the result of the alternating current from the power source making the lock vibrate.)

This experience can help you get a mental picture of the inner workings of an EAC system. A basic EAC system consists of a reader, a controller, and an electric lock. In my example, the receptionist's eyes are the reader that allows her to recognize you. Her brain is the controller. If her brain is convinced that you belong inside, it will send a signal to her finger, ordering it to press a button and release the lock.

More About Readers

Readers are mounted on the outside of doors, and are the the only part of the EAC system most people see. In a modern EAC system, the readers are designed to recognize codes (something you know), credentials (something you have), or biometrics (something you are). If the system uses a code reader, you enter a Personal Identification Number (PIN) into a keypad to identify yourself to the system. With a credential reader, you would present a card or key fob. A biometric reader must read a part of you.

Popular biometrics include fingerprints and hand geometry. Finger vein patterns are also becoming a popular form of biometric. Retinal scans have been used for some time. They are not very popular in business environments, and are usually reserved for high end systems. Finally, facial recognition is a developing technology. While this technology is very useful for investigations, it has not yet gained wide acceptance as a method for access control.


Keypads are the simplest and least expensive form of access control readers. Keypads, such as those produced by IEI provide a simple method of entering your code.

However, Keypads have two drawbacks: codes can be easily shared and easily stolen. Because of these two drawbacks, keypads should not be used in a high-security application unless they are combined with a credential or biometric. This "two factor authentication" is a very secure approach to access control.

Hirschtm Electronics produces a more sophisticated keypad, known as a ScramblePad which greatly reduces the threat of stolen codes. The ScramblePad arranges the numbers on the Keypad in a random pattern each time it is used. This makes it impossible for someone to learn your code by watching the action of your hand, since you will use a different physical motion each time you enter a code. Because the numbers do not stay in a fixed location, an intruder cannot guess your code by looking at the pattern of wear on the keys. The ScramblePad is also designed in such a way that it cannot be read from an angle. Someone looking over your shoulder cannot steal your code, because the numbers on the keypad are invisible to them.


Access control credentials usually come in the form of cards or fobs that can hang on your keychain. The most common credentials are Radio Frequency Identification (RFID) cards. RFID cards can be read from a distance. In some cases, they do not have to be removed from your pocket in order to be used. The most common RFID cards use a format developed by HID Corporation and are incorporated into products from a variety of manufacturers.

Biometric Readers

All biometric readers are designed to scan a unique part of your body and create a digital template. The template is created when you "enroll" in the access control system. When you come to a door and request admission, the EAC system scans your fingerprint, etc. and compares the new scan to the stored template. If the two match, you're in.

Fingerprint readers are now standard equipment on many laptop computers. For access control purposes, Bioscrypt produces excellent, widely used fingerprint readers.

Hand Geometry readers create a template from the size and shape of your hand. The Recognition Systems readers are widely used in banking and other industries.

Finger Vein readers are similar to fingerprint readers, except that they look below the surface of your finger to scan your vein pattern.

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