All U.S. government and many corporations have now incorporated a contactless reader as an access point to their facilities. Some companies have incorporated a biometric component to this credential as well. The older systems deploy a simple proximity card system as the gate keeper. But as the security requirements have become stronger and the cost of ISO14443 standard systems have become cheaper, the world is rapidly adopting this new standard. This market shift is partially driven by the US government’s adoption of the mandated Personal Identity Verification (PIV) standard. There is a rich ecosystem of suppliers and integrators for this standard.
Lots of companies use proximity cards to control physical access. An employee holds their card within a few inches of the reader; the reader receives a unique id from the card and transmits it to some central computer that tells it whether or not to open the door.