Access Control Systems Information

Access cardAs it becomes increasingly critical to maintain secure facilities for the protection of both IP and physical property and for the well-being of building occupants, it is important to carefully select and maintain a system to allow people to enter that should enter and keep out those who should not.


Access control systems are used to identify people before granting access to secure facilities. These include card and pod readers as well as biometric equipment to identify:

  • fingerprints
  • thumb prints
  • palm prints
  • retinal scans
  • facial features
  • voice patterns

Most access control systems consist of a wall-mounted access panel at the point of entry, a single-board computer called a door commander, and one or more identification sensors. The access panel mounts on the public side of a secure door and is often monitored by a camera for confirmation and redundancy. The door commander runs an algorithm that matches a user’s identification to a database of authorized entrants.


Access cards are basically an electronic "key.” An access card is used to gain access through the doors locked and monitored by the access control system. Every access card is uniquely encoded. Nearly all access cards are roughly the same size as a credit card and can easily be carried on a lanyard with a photo ID or in a purse or wallet.

Card readers are the scanners used to electronically "read” a magnetic access card. Card readers may be of the "proximity" type (requiring that the card be held near the reader) or the "insertion" type (which requires sticking the card into the reader). Card readers are usually mounted on the wall near the exterior (on-secure) side of the door that is controlled.

Key fobs are pocket-sized security devices with built-in authentication installed in the unit that allows the door commander to either grant or deny access to a particular facility or area of the facility. The fob works using radio frequencies for identification and can be programmed to periodically change the ID frequency. Key fobs are usually passive; they do not require an internal battery. Key fobs are popular at medium security facilities because they involve very little effort by the user and can be easily programmed and reprogrammed.

Biometric access control systems include a fingerprint, iris, voice, and facial recognition systems. Fingerprint systems require the user to place an index finger on an image reader that compares multiple points on the finger to an encrypted formula. These biometric access control systems are used to control multiple doors and can be integrated with existing door-lock mechanisms. Iris recognition systems use a camera to compare a black and white image of the eye to a stored template. Products that compare up to 250 iris features can be used alone or in conjunction with a fingerprint access control system. Facial recognition systems compare images of faces to a database of stored images. Integral software is used to measure key nodal points such as distance between eyes, width of nose, depth of eye sockets, cheekbones, jaw line, and chin. Biometric access control systems that use voice recognition technology are used to control access to account information and financial data. They can also be used to control access to telephones and other communications equipment. Before Biometric access controla transaction is authorized or access is granted, a user’s spoken voiceprint is compared to stored information, such as a set of spoken digits.

Access control keypads are devices that may be used in addition to or in place of card readers. The access control keypad has keys that look similar to the keys on a telephone. The access control keypad requires that a person desiring to gain access enter a correct code. When access control keypads are used in concert with card readers, both a correct code and valid card must be verified before entry is granted. When access control keypads are used instead of card readers, only a correct code is required to gain entry. Keypads are the simplest access device and likely the least secure because users share a password or multiple assigned passwords are used leaving the system vulnerable to “over the shoulder” observation of the code used.


Traditionally, access control systems have been used to secure buildings and facilities. Access control systems were considered a security tool that let authorized personnel enter a building or area. While access control is certainly used for these purposes, advanced access control systems can offer an array of tools and benefits that may not have been considered. Beyond traditional security, access control systems can help any company or organization increase efficiencies of operation (and reduce costs) by enabling access system integration with many of the enterprise operation software products and solutions currently available.

Related Information

CR4 Community—Design Build Service Company / Access Control System

CR4 Community—Intelligent Building Management System

IEEE Spectrum—Fast Start for World's Largest Biometrics ID Project

IEEE Spectrum—Biometrics Researcher Asks: Is That Eyeball Dead or Alive?

Images credits:

IDenticard Images / CC BY-SA 2.0

Lgate74 / CC BY-SA 3.0

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