Laying the groundwork

Building Operating Management, May 2000 by Schumacher, Jeff

CARDS AND READERS ARE THE BUILDING BLOCKS OF AN EFFECTIVE ACCESS CONTROL SYSTEM

Access control, as just one component of a security program, is generally put into place because it simply is not feasible to lock all doors all the time. Electronic access control grants users access to some areas and denies access to others. So electronic access control must offer something more than just the ability to unlock doors. In fact, electronic access control systems are commonly used for numerous additional functions.

Even where the only function of electronic access control is granting or denying access to a room or area, there can be advantages over the use of keys. Consider, for example, the complexity of using keys to to selectively control access to just a dozen rooms or areas at a facility. How many keys would be required to implement the level of security appropriate to your particular facility? How would those keys be issued and controlled? Could they be copied? Would a key system provide the ability to track when and by whom the door was unlocked?

Electronic access control also eliminates the time-consuming process of re-keying locks. Changes to a specific area's access level can be quickly accomplished through the system management software.

CARDS AND READERS

There are a variety of different card technologies on the market today. Some are better suited to higher security applications, with others providing significant cost advantages for the large user.

Magnetic stripe is still the most commonly used technology. A standard card's stripe contains space for up to three separate tracks, although only one track is typically used for electronic access control. This means that one card can be used for different purposes, such as electronic access control and debit systems, each utilizing a different track on the card. Encoding equipment may be purchased by the end user to allow the stripes to be coded at the user's facility, if desired.

Barium ferrite is an older magnetic card technology that encodes cards by placing pieces of the material within the card during manufacture. The pattern created determines the code, which is read and decoded by the system. Although the technology is not current, many of these cards are still in use.

A Weigand(TM) card uses thin wires embedded into the card when it is manufactured to create the code. These cards are generally tough, and difficult to duplicate.

Cards that use bar codes are easy to make and easy to duplicate. This type of card - in which the code is optically read - is generally appropriate for only low to moderate security applications where low cost is important.

Proximity cards or tokens communicate with the reader via radio waves, allowing the card to be read without actually touching or swiping through the reader. Several different types of proximity technologies are available in the marketplace today, providing varying ranges of distance from the reader from which the cards can be read.

So-called smart cards utilize a chip which processes and stores data on the card. The information is typically used for purposes other than access control, such as account balances in a debit system. Smart cards are increasingly in use at universities because the card enables students to easily take their account balance with them. Use of smart cards is increasing, but they are not yet considered commonplace in the United States.

It is also possible to combine more than one technology on a single multiple-technology card. For example, a corporation with two facilities - one utilizing magnetic stripe cards and readers and another using proximity cards and readers - might be able to use one card employing both technologies to provide access to the two facilities. In an upgrade, this approach can make it possible to continue to use existing cards.

In all cases, the key is to select the cards and readers that meet the specific needs of the application.

KEYPADS AND ACCESS CONTROL

Another electronic access control option is the use of keypads. Some applications involve keypads only, while other systems employ both cards and keypads. Generally speaking, keypad-only systems are on the low-security end of the scale, providing access to anyone with the ability to push the right buttons in the right order. Sometimes these units are used as a simple measure in a first line of security, where additional and presumably more effective methods are also used elsewhere in the security program. For example, a keypad might be used to open a motorized gate to an employee-only parking lot or area, where an additional key or card reader is required to gain access to the facility.

The problem with most keypad-- only systems is that an observer can steal the code and gain entry simply by watching someone using the proper access code. At least one manufacturer produces a keypad system which rearranges the numerals on the keypad each time the unit is used as a means to deter the would-be code stealer.

Combination card and keypad systerns are common in applications where a higher level of security is mandated, such as airports. In this configuration, a user must present a valid card to the reader, then enter the accompanying PIN code (similar to using an ATM machine) before the system will grant access. This approach provides a higher level of security than could be achieved by the use of either device individually.