Proximity readers are among the simplest access control systems to install and use. The principle is simple: they are encoded to read and respond to electronic signals from access cards, and only to cards that are specifically authorized. Unlike the swipe cards used at ATM readers at groceries and other stores, most proximity cards don't require contact with the reader or a Personal Identification Number (PIN) to work. Proximity is enough, with sensitivity limited to as little as an inch or two or expanded to over a foot - especially useful for handicap-access doors, parking garages, etc.

With some systems, contact is required: you simply touch the card to the magnetic-responsive face of the reader. Alternatively, or additionally, a numeric key-pad is used in conjunction with the magnetic coding embedded on the card.

Proximity readers are also extremely versatile: they can be installed on computers, file cabinets, office doors, building entrances, or interconnected throughout a corporate enterprise, allowing an authorized card holder to access the home office in New York and the warehouse in Miami with equal ease. Some don't even need to be wired, but operate using long-life rechargeable batteries; most are hardwired through a single-gang box, and some have a battery back-up power system.

Like other access control systems, proximity readers (for example, those used in computer networks) can be programmed to accommodate static passwords, username and password systems that can be changed as personnel come and go, or bundled with compatible software that increases controllability. "Slave" units can be installed to control printers, photo-copiers, and other LAN-connected hardware to track and monitor employee use (and control abuse).

Systems are also extremely flexible in limiting physical access to specific personnel, allowing all employees to gain entry to certain parts of a facility, but only those with specially coded cards to enter a boardroom, supply room, secure file room, etc.

A proximity card system can be one of the most affordable access control systems you can invest in, and not just for businesses. Securing homes with proximity readers - and limiting cards to family members - is a popular option for some households.

Whether it's a simple, one-door controller with just a few cards or a company-wide system that authorizes tens of thousands of users, a proximity reader system that's right for you is available, affordable, and reliable.