Proximity cards go the distance

Jan 1, 1997 12:00 PM, By GEORGE PARTINGTON

Convenience is desirable in door entry systems, and what is easier than approaching a door, opening it and walking in, just as if it were unlocked? With distance proximity technology, such ease of ingress can be achieved while premises remain secure, with only credentialed personnel gaining access. A credit card-sized card can be kept in a wallet, briefcase or purse and when a person walks within three feet of a door, a reader will recognize the card and unlock the door. Security in this case has no invasive or threatening aspects, and it can even be aesthetically pleasing. For example, the Westinghouse line of readers has won a design award and blends well with the professional office. Cotag, Cambridge, England, has designed glass panels that house the readers' antennas and become a decorative element of a building's interior design.

Radio frequency (RF) makes it all possible. Distance proximity readers - usually recognized as those that read at distances of one foot and greater - use an antenna that transmits RF, usually low frequency RF. Don Small, vice president of marketing for HID, Tustin, Calif., describes the low frequency RF signal as radiating a glow in a spherical pattern. When an access card enters the glow, or the RF field, it transmits a signal back to the reader, which then decodes the signal and grants or denies access.

Does the convenience come at a trade-off in the level of security? Niel Skousen, senior engineer, special projects group, at Scientech, Idaho Falls, Idaho, thinks not, and risk assessment is a large part of Scientech's security system design, installation and training work. "The issue," says Skousen, "is not necessarily can I fool it in real time, but can I copy the card information and duplicate or vary a card to obtain access surreptitiously?" The answer is yes, says Skousen, but the complexity of the current systems means an expert would have to jump through quite a few hoops to fool a reader. Is it worth it? "Probably not," Skousen surmises. "It's probably not the weak link in the system."

Different ranges for different uses, The market for RF proximity technology in access control applications can be broken down into three areas: proximity, distance proximity and long range proximity. Also within the overall proximity category are asset tagging and tracking. Proximity refers to any reader that does not require swiping, insertion or contact with a reader - the card merely has to enter the reader's proximity, which could mean as close as an inch. In the proximity segment, the most popular products are readers that have a range of about 10 inches. Brent Duncan, marketing services manager for Westinghouse Security Electronics, Santa Clara, Calif., says the most popular product in his company's line of DigiReaders is the DR4208 with a read range of up to 7-10 inches. Don Small of HID says the ProxPro, with a read range extending 8-10 inches, comprises 50 percent of the readers HID sells.

A benefit of these readers - also offered by Motorola Indala, EyeDentify, Cotag, Cardkey and Keri, among others - is their durability. No moving parts means no wear and tear. The cards are "passive," meaning they do not require a battery to send an RF signal back to the reader. The power to retransmit the signal is provided by RF output from the reader. The cards are as durable as the materials used in their manufacture.

Hands-free access What about the convenience of a longer read range? Most companies that offer short proximity readers are also active in the distance proximity market, which includes readers with a read range of about three feet. These readers are used for door entry, vehicle access and parking applications, and asset tagging and tracking, or RFID. A benefit here is the hands-free access already mentioned: the RF can penetrate wallets and purses to read the card, provided there is no metal interference.

These products fall within Americans with Disabilities Act guidelines for building access for the handicapped. A battery-powered card is often needed to transmit a signal to the reader at this longer range. The battery lasts about five years, which manufacturers point out is still a longer life than most other card access technologies. The DR4238 from Westinghouse and HID's MaxiProx provide a read range of three feet with a passive card. Advantage Series Proximity (ASP) cards and readers from Motorola Indala, San Jose, Calif., also use passive card technologies for reads of up to 28 inches

Many of these readers can go to six feet and beyond, which is useful for automobile access, but the three-foot range is well-suited to door entry. Ranges beyond three feet present problems with controlling the radio signal and with accidental triggering of access when credentialed personnel merely walk by. Imagine a read range of six feet in a hallway only five or six feet wide - every door in the hall would be triggered when someone carrying a tag walked by.

Readers with a three-foot range can also be used for vehicle access control. For example, a loop antenna can be placed under the ground of a lane into a parking lot, while a tag is affixed to the bottom of the vehicle. The tag is read as the vehicle pulls up. Don Sturgis, product manager at Cardkey, Simi Valley, Calif., says the company's L5511 Reader can be so used, or it can be mounted on a post next to the lane entering the parking area. With the three-foot read range, a driver could hold up a tag without rolling down the car window.

These readers also avoid some of the problems engendered by higher frequency RF. HID's Small points out that high frequency beams can reflect off conductive materials - even metal studs in a wall - creating multipathing. You'll find the beam is zooming all over the room or through the wall into the room next to it, says Small. The low frequency beam, on the other hand, goes such a short distance that it cannot create multipathing, Small adds. It can't reflect off anything.

Long range for vehicle access Vehicle access applications are a major growth area for RF technology readers. Rick Muller, vice president of Select Engineering Systems, Hialeah, Fla., says his company developed the Ranger 20 because of the growing demand for long range readers. Ranger 20 - designed for parking applications and gated residential communities - can read as far as 20 feet, while a vehicle is moving at up to 35 mph. It can also be tuned down to read at two to five feet for building access applications, says Muller. According to Muller, the reader uses an RF back-scatter technique developed by the military to send fully encrypted data, so a card number cannot be read by someone monitoring data flying through the air.

UltraProx from EyeDentify, Baton Rouge, La., reads up to 20 feet and is used mostly for vehicle access and parking applications, according to Chris Crifasi, manager of business development. It's used like a toll tag, says Crifasi. You put the tag either hanging from the rearview mirror or attach it directly to the inside of the windshield. Access is granted without the driver having to roll down a window or extend an arm, which could be a security risk.

Amtech Systems Corp., Dallas, has the SmartPass line for such applications. Cotag and Cardkey, which specialize in personnel access and asset tracking, are part of Amtech's Electronic Security Group. Like SmartPass and Motorola's ASP, most of the products in this reader category are designed for asset and fleet tracking and management.

Asset tagging and tracking Another spin-off of RF technology are products that monitor tagged assets. With miniaturization of office equipment, such as laptop computers, workers are beginning to take their office with them, to their homes or for business travel, leading to a significant risk of theft.

But with products such as ASGI's Intelligent Tagging System, these assets can be tagged with RF cards, which are programmed to present an alarm condition when taken off the premises, unless a corresponding tag worn by authorized personnel is also read. The reader looks for the functional linkage between the person and the person's laptop, says Stephen Briggs, president of ASGI, Sterling, Va.

A line of cards and readers from Cotag, Cambridge, England, are used in hospitals, except the assets are the patients. Wrist tags are attached to newborn babies and programmed to correspond to tags worn by authorized nurses and the baby's mother. If anyone unauthorized tries to leave with the baby, an alarm results. The tags are also used by patients to alert hospital personnel if they have left assigned areas. HID, Westinghouse, Motorola Indala and Cardkey also offer such RFID card and reader systems.

The Next Wave Niel Skousen has seen his share of technological revolutions. In the case of radio frequency, he says, you have an entire technological segment that is beginning to go nuts. In the last 10 years, you have a confluence of technological drivers from a number of areas, such as the personal computer and associated fabrication techniques, such as miniaturization. Then you have personal wireless communications, which includes cell phones and the higher-end cordless phones. They are impacting us in the security world in RFID technology and the advanced prox cards.

So markets having nothing to do with security and that are ten times bigger are driving R&D. Ten years ago, if you wanted to make a low-powered 900 megahertz transmitter you were into big dollars, says Skousen, who is senior engineer, special projects group at Scientech, Idaho Falls, Idaho. Now, you can buy the chip sets, you can buy the pieces and components and away you go. And Skousen says the next wave of products from the world of personal communications systems will use 1.7 to 2.5 gigahertz radio frequency. Having seen wireless communications impact the security industry once, Skousen says it is reasonable to assume it will do so again. The impact could mean new types of cards or longer-range, better readers, but for access control it could also become apparent that the current three-foot range is ideal. Other aspects of security systems, such as overall connectivity, could be altered, however, leading to completely wireless installations.

10 questions to keep in mind when shopping for proximity readers Passive or active card?

Passive cards require no battery and do not wear out; active cards use a battery that has to be replaced every 5-7 years.

Reads affected by shielding, metal? Radio frequency waves are subject to interference, particularly from metal surfaces.

Field programmable cards? Waiting for manufacturers to supply programmed cards can cause intolerable delays.

Reader flexibility, appearance? Most readers come in a variety of sizes, including mullion mounts, but smaller size correlates to shorter read ranges. Readers become a part of a facility's look.

Multiple uses for card? Some cards can be equipped with magnetic stripe or bar coding for uses such as cafeteria or fuel account debiting.

Is the card badge-ready? Can the tag be customized with graphics and photos, and, if so, is dye-sublimation (in which ink permeates the top layer of PVC material for image durability) available?

Can reader be integrated with existing Wiegand wiring? This can make installation and migration to proximity readers easier.

Is reader available with a keypad? A higher level of security can be provided with a keypad, which can beprogrammed to require a card and a PIN for entry.

What type of antenna? Types of antenna, such as side read, loop and ground loop, will affect read and installation flexibility.

Is asset tagging and tracking needed, available? Does your reader need to have the ability to track assets, vehicles or employees' time and attendance?

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© 2008 Penton Media Inc.

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