ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Tuesday, January 23, 1996 TAG: 9601230040
SECTION: EXTRA PAGE: 3 EDITION: METRO
COLUMN: At Home with Technology
SOURCE: DAVID BUTLER
Q: I've always been fascinated by entry control devices I've seen in offices and high-rise apartment buildings. Are variations available for single-family homes?
A: Access control systems allow property owners to restrict who enters their premises. They fall into two broad categories. With one type, authorized persons gain access with a numeric code or an electronic key. The other type is essentially an intercom with a remote controlled door lock. Falling prices and growing concerns over crime have ignited interest among single-family homeowners.
The numeric keypad is the most common (and least expensive) mode of access control. The keypad is mounted at the door used by family members - usually the kitchen or garage entrance. Instead of scrounging around for the door key, you simply enter a numeric code. This triggers an electric door strike which unlocks the door. The strike plate is the part of a door frame that holds the lock plunger.
More elaborate systems keep an entry log with the time and date along with the corresponding access code. You can even give out temporary codes, for example, to your cleaning service or an appliance repairman. The codes can be set to expire at a specified time or restricted to certain hours and days.
The rapid decline in microelectronics prices has led to even more convenient and flexible access control products - in particular, the electronic "key." One type resembles a credit card. To gain access, simply insert the card in a special reader. Lost or stolen cards can easily be deleted and reissued. Card-based systems are an ideal for anyone with an automatic entrance gate.
Proximity devices go a step further. Instead of having to insert your key, you only need to pass it near the reader. The key contains special circuitry that gives it a unique radio signature. One version is small enough to fit on your key ring - one less thing to worry about losing.
Besides the obvious convenience, an access control system makes it more practical to keep your doors locked at all times. In case of a malfunction or power outage, most systems give you the choice of "fail secure" (locked) or "fail safe" (unlocked). Nonetheless, you should continue to use your dead bolt locks - especially before turning in for the night or leaving your home unoccupied.
A growing number of private communities are installing access control gates. Depending on the size of the community and number of entrances, access control can be partially or totally automated. One method relies on a small proximity tag mounted on the interior of each resident's windshield. A valid tag causes the gate to open as the vehicle approaches.
If you just want to have remote control of your entrance door lock, you should consider a door intercom. Most have a low-voltage relay designed to operate a door strike (or gate opener). Once you screen a visitor, simply press a button on the intercom station to release the door.
Some front door intercoms are designed to connect to a telephone line, eliminating the need for a dedicated station. When a visitor presses the call button, your telephones will ring in a distinctive pattern. You can "answer" the door or activate the door strike from any extension. If you have call forwarding, you can even greet visitors from your office telephone!
The Cutting Edge: Biometric identification, once the domain of science fiction, is now a viable option for high-security buildings. Biometric access control systems are based on the premise that certain patterns are unique and cannot be loaned, lost or stolen. Systems are available that can correlate iris and retina scans, voice print, fingerprint and signature recognition.
To receive a list of companies that manufacture access control systems and door intercoms, please send $1.50 and a self-addressed envelope to David Butler F-548, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products. You'll also receive sources for automatic gate openers.
LENGTH: Medium: 73 linesby CNB