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NFC Technology - How It Works in Access Control

Deciding between NFC and RFID Access Control? Find out more about RFID first!

NFC Technology

Near field communication (NFC) technology is a type of communication, which is based on the induction of electromagnetic fields developed mutually between two antennas of NFC technology enabled devices. The communication between two devices in an NFC system takes place through a stack of communication protocols. Loop antennas are commonly used in the common applications of near field communication for generating magnetic fields when brought closer to each other. The normal range operational distance between two devices, for example an NFC reader and an NFC access card is less than 1.6 inches or 4 cm.

An air interface between two devices – the most common paradigm being known as an NFC card and NFC reader, is established at 13.56 MHz frequency, which is a reserved band for industrial, scientific and medical uses generally referred to as ISM band. This band is free and does not involve complex licensing or other major regulation procedures. The range of data rate of air interface established between two NFC enabled devices normally lies between 106 kbps to 424 kbps. The GSMA group and NFC forum are two major bodies that define and regulate the NFC communication standards.

Passive and Active NFC Devices

One of the greatest innovations of the NFC standard is the differentiation of NFC devices into passive and active categories. In a standard NFC system, there are two devices that communicate with each other. We can usually distinguish these into an active NFC device and a passive one. The main difference is that the active device in the NFC system has to be powered, whereas the passive device doesn’t need any sort of power or energy to it. This makes NFC technology ideal for, say NFC smart cards, which don’t have a battery or power port on them.

When the devices enter in proximity to each other, the active device induces a current on the passive NFC smart card’s NFC chip using electromagnetic induction, and this triggers the passive NFC device’s chip to start transmitting signals. These signals are then picked up by the active device, because the two devices are already in close proximity to each other, and the connection is established.

This is also part of the reason why the devices need to be in such close proximity to each other. While standard RFID communications can occur over greater distances, NFC was purposely limited to these close range applications because of the power of separating an NFC system into an active device like a reader, and a passive device like an NFC smart card.


NFC in Access Control Applications

NFC technology is being used in multiple applications nowadays. Notably, it can be found in cloud computing access control, physical access control, system security, property security, but there are of course many other non-access control related applications. The fundamental principle of NFC technology in all applications remains the same one way or the other.

In the vast majority of these access control cases, NFC technology employs one NFC reader and one NFC card or key. The key is the passive device, and is normally coded with the tag data, which contains the information for authorizing the holder to access the designated room or area. That key is tapped over the NFC reader, the active NFC device in the NFC system, which reads the information with the help of NFC communication protocol sets, and grants access to the authorized person. This communication is not limited only to authenticating and granting access to the authorized person, but also records the access information, time, period of access, and many other parameters.

Similarly, an NFC chip is also used in NFC enabled devices, such as tablets, mobiles and laptops to access the cloud based network and system resources over the internet. In this NFC access control system, the smart card data is transmitted over the internet to the centralized location for granting of access into the entitled cloud computing resources.

There are many different types of readers that are extensively used in different access control applications; among those readers, an IP based modern access control reader is a highly featured, secure and reliable access control device available in the market. This reader can easily be integrated into an IT network for achieving the robust and secure access control with many additional security and operational features.

A latest form of NFC access control system is being managed through the mobile applications installed on the smart phones. Those mobile applications act as the key or an information tag for the NFC reader. They are still passive, though, as the NFC chip does not need to be powered on until it is in active communication with the NFC reader. When the mobile is swiped or tapped over the NFC reader, a communication channel is established over NFC radio waves, and data transactions take place to authenticate the authority of the user to access the secured area, resources or applications.

NFC application unlock door
‍NFC Applications in Action.


Owing to the huge growth in the cloud computing applications/services and the mobile workforce, many industry experts believe that a huge potential of business growth is available in the domain of NFC based access control systems applicable to both digital and physical resources. So, it is very predictable that mobile phone would extensively be used as NFC card to get secure access to your office, home or other secured areas in the near future.