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How Does Proximity Access Control Work?

October 4, 2023

No time to read? Here’s a summary:

  • Proximity access control refers to security systems that assess the validity of access requests without requiring physical contact with a credential.
  • Proximity card technology blends radio frequencies, intricate hardware components, and advanced security protocols for no-contact data transmission.
  • Proximity access control provides enhanced security and easy management both for administrators and card users.

Proximity cards, also known as prox cards, are effective and convenient credentials for access control ID verification.

But how do proximity cards work? Keep on reading to explore the intricacies of this popular security solution.

Understanding Proximity Access Control

Proximity access control refers to access control systems that use proximity cards to identify users before deciding whether to grant access.

Proximity cards use electronic radio frequency identification (RFID) signals to communicate with door readers. Unlike earlier magnetic stripe cards, which require direct contact with a reader to activate the access control process, proximity cards only need to be in close proximity to a reader.

The Science Behind the Technology

At the heart of every proximity card is an RFID chip containing a unique identifying number that is specific to the card.

The Role of Radio Frequencies

When a proximity card comes within range of an RFID reader, the reader emits a low-power radio frequency. This radio wave interacts with the antenna in the proximity card, creating a small electrical current.

This current powers up the RFID chip, allowing it to transmit its stored data back to the reader.

Data Transmission

Once powered, the RFID chip sends its unique identification number (and any other stored data) back to the reader via the antenna. This transmission happens almost instantaneously, allowing for swift access or denial based on the data received.

Security Protocols

Many proximity cards use encryption to ensure the security of the data transmission. This means the data sent from the card to the reader is scrambled, making it difficult for potential eavesdroppers to decipher, while the intended RFID reader, with the correct decryption key, can understand the transmitted data just fine.

Passive vs. Active Cards

There are two main types of proximity cards: passive cards and active cards.

Passive cards don’t have their own power source. Instead, they rely entirely on radio waves from the RFID reader to power the chip. Passive cards are commonly used for access control purposes due to their simplicity and cost-effectiveness.

Active cards, on the other hand, come with their own battery source. This allows them to transmit data over longer distances. Active cards are typically used for more complex applications, such as vehicle tracking and asset management.

Frequency Variations

Different proximity cards operate at various frequencies depending on their intended use. Common frequencies include:

  • Low Frequency (LF): Operating at around 125 kHz, these are most commonly used for building access and security.
  • High Frequency (HF): Operating between 13.56 MHz, these are used for more data-intensive applications like mobile payments or ticketing systems.
  • Ultra-High Frequency (UHF): Operating between 856 MHz and 960 MHz, these are used for applications that require reading data from a longer distance, such as supply chain management.

Benefits of Proximity Access Control

ICT installed at door

Enhanced Security: Proximity cards offer a higher level of security than traditional keys and even magnetic stripe cards. A proximity card’s unique identification number, when properly encrypted, makes it more difficult to duplicate.

Convenience: Users don't have to fumble with keys or swipe cards through a reader. Simply being near the reader is enough to be granted or denied access.

Durability: Prox cards are less prone to wear and tear since they don't require direct contact with a reader.

Integration Capabilities: Most proximity access control systems can integrate with other security systems for a comprehensive security solution.

Easy Management: Administrators can quickly add, remove, and tailor access permissions to different staff needs. This easy adjustability makes proximity cards ideal for businesses with high employee turnover or multiple access levels.

Applications of Proximity Cards

Proximity cards are versatile and useful in many settings, including the following:

Offices and Corporate Buildings: Control who can access certain floors or rooms.

Hospitals: Ensure only authorized personnel can enter specific wards or access restricted medications and equipment.

Educational Institutions: Restrict access to labs, libraries, or dormitories.

Government Facilities: Enhance the security of sensitive areas.

Parking Lots: Allow only authorized vehicles to enter or exit.

Mammoth Security and Access Control

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It's crucial to engage with seasoned access control specialists to establish an access control system tailored to your site's distinct security and operational demands. At Mammoth Security, we collaborate with you to choose the most suitable products for your site security.

For a no-obligation consultation with a friendly security professional from our team, simply complete the form below. We'll promptly reach out to arrange a free site evaluation and determine your specific needs.




Proximity access control refers to systems that use proximity cards to identify users and decide whether to grant access.

Proximity cards use electronic RFID signals to communicate with door readers without direct contact.

Unlike magnetic stripe cards that require direct contact with a reader, proximity cards only need to be near the readers.

The RFID reader emits a low-power radio frequency that interacts with the antenna in a passive proximity card, powering the RFID chip and allowing data transmission.

Powered by its own battery or a transmitted radio wave from a reader, the RFID chip sends its unique identification number and any other stored data to the reader almost instantly.

Active cards have their own battery source for longer data transmission distances, while passive cards rely on radio waves from the RFID reader for power.

Most building access proximity cards operate at a Low Frequency (LF), around 125 kHz.

Proximity cards offer enhanced security, convenience, durability, integration capabilities, and easy management.

They are used in offices, hospitals, educational institutions, government facilities, and parking lots to control access.

Prox cards don't require direct contact with a reader, making them less prone to wear and tear.

Administrators can quickly adjust access permissions, making it easy to manage access for different staff needs.



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