A proximity reader reads a credential held near it, usually a low-frequency card or fob at 125 kHz. It sends the card’s identifier to a controller, which decides whether to unlock. The technology is convenient and durable, but older formats are simple to copy.
Proximity is the workhorse credential of commercial access control: cheap, rugged and familiar. Its weakness is that the card only announces a number.
Read range and mounting
Read range is short by design, a few inches, and mounting on metal or behind a metal frame shortens it further. Test the chosen reader on the actual door before ordering hardware for a whole site.
The cloning problem
Low-frequency cards often transmit a fixed identifier with no authentication, so a copied card looks genuine. Where that matters, use encrypted smart cards or mobile credentials, and revoke lost cards immediately.
Related:Glossary: Access control systemGlossary: NFC access control