What technology is commonly used in proximity card systems?

Proximity card systems primarily utilize RFID (Radio Frequency Identification) technology. RFID works by using electromagnetic fields to transfer data between a reader and a tag, which in the case of proximity cards, is embedded with a chip that stores user information. When a card is brought within a certain range of the reader, usually a few inches, the reader communicates with the card via radio waves, allowing for secure and contactless access control.

This technology allows for quick and efficient identification and authentication without the need for physical contact, which enhances user convenience and reduces wear on the card and reader systems. The range and data transfer capabilities of RFID make it particularly suitable for applications like access control, where a seamless and fast interaction is critical.

Other options, while they have their own applications, do not fit the characteristics and functionality required for proximity card systems. For instance, Bluetooth is more commonly used for short-range communication between devices but is not typically employed in access control systems designed specifically for RFID technology. Infrared (IR) requires a direct line of sight and is not practical for the convenience required in proximity systems. Wi-Fi, though capable of transmitting data over longer distances, is generally used for broader networking purposes rather than the specific, short-range access control needs fulfilled by RFID