Proximity card

thumb|250px|right|A passive proximity card for door access.

thumb|250px|A proximity card controlled turnstile

thumb|250px|right|A passive proximity card with the plastic casing opened to show components: antenna coil and smart chip integrated circuit (black object bottom center)

thumb|250px|right|Anatomy of proximity card: coil and IC

thumb|250px|right|The proximity card coil of an electronic fare collection system

A proximity card or prox card, also known as a key card or keycard, is a contactless card technology that can be read without being inserting into a reader device that was required by earlier developed contact type cards: magnetic stripe cards (credit cards, etc.). They are typically used as keycards for facilities access controls (doors, gates, etc.). In its simplest form, while being held near an electronic reader, they transmit a facility code (also called a "site code") and a card serial number Readers usually produce sound and/or show a status light to indicate the card has been held close for enough time to be read.

The term "proximity card" generally refers to the original 125 kHz devices without smart chips that do not hold more data than a magnetic stripe card and are distinct from devices that hold more data such as 13.56 MHz RFID and contactless smartcards or 900 MHz devices that can also be used for facilities access control when configured with a facility code and card serial number. Prox cards can be used for rough distance estimation applications. Passive prox cards typically have a longer read range of up to and read by simply holding the wallet or purse near the reader. Proximity cards with smart chips can hold other types of data like history of time and attendance or biometric templates.

Types

Passive cards

125 kHz passive cards are powered by radio frequency signals from the reader resulting in a limited range and typically must be held close to the reader unit.

Active cards

125 kHz active prox cards, sometimes called vicinity cards are powered by an internal battery. They can have a greater range, up to 2 meters (6 ft). Active 900 Mhz UHF smart cards can reach up to 150 meters (500 ft) and are often used for applications where the card is read inside a vehicle, such as security gates which open when a vehicle with the access card inside approaches, or automated toll collection. Often, the first several serial number bits can be made identical, while the facilities code bits can be unique to allow for access control for different companies when using identical serial number bits.

For smartcards, a numbering system is internationally harmonized and allocated by Netherlands-based NEN (registration authority) according to ISO/IEC 6523 and ISO/IEC 15459 standards.

Proximity card

Types

Passive cards

Active cards

See also

References