Once associated only with banks, jewelry stores, or museums, access control systems are now playing a much greater role in the overall design of all types of commercial buildings. Increasingly seen as a necessary part of the comprehensive design package, access control has prompted the growth of security technology. What many people don't know is that even the simplest of current systems can perform in a manner previously associated with costly and complicated security management systems, often without the big price tag. This underlines the importance for specifiers, designers, and installers to keep pace with the continuing evolution and use of these systems.

In their simplest form, access control systems provide the type of features and functions normally associated with “burglar alarms” or intrusion detection systems; electromagnetic locks, door position switches, and motion detectors. Although many of these devices are still being used as part of an access control system's basic hardware package, it is actually the software and other PC-based features that provide the level of sophistication found in today's systems.

Nuts and bolts

Controlling the flow of traffic in and out of a building is still at the heart of every access control system. Entries are secured with electromagnetic locks or strikes, which can be overridden through the use of a keypad or card reader. Often, the inrush current associated with these locking devices mandates that each door be equipped with a dedicated power supply, usually located above the ceiling near the secured door. Additionally, secured doors are equipped with magnetic contacts that monitor door status after a valid entry or exit event, ensuring that a door cannot be propped open or left ajar for later use by individuals normally not permitted entrance to the facility.

Quite often, an additional security device is used to both monitor and permit exit through a controlled entry. Any one of several devices located near the interior side of a door can be used to exit, including a second keypad or card reader, request to exit pushbutton, crash bar that briefly transfers power from the locking device to the hinge side of the door to allow exit, or a request to exit motion sensor. This device unlocks the door upon the disruption of a passive infrared beam by a person approaching the exit.

All of these devices are normally hardwired to an “intelligent controller” that monitors a given number of controlled doors (anywhere from two to eight), transmitting their status through a hardwired connection (RS-422) to a main or master system controller. These intelligent controllers are usually installed in a remote location of the facility, in close proximity to the locked doors they support, while the master system controller is typically located in a secure, constantly manned area. There, a dedicated computer workstation is connected to the main controller to monitor the status of all locked doors.

Communication between the master controller and operator's workstation can be accomplished via a direct serial connection (RS232/RS422); a 10/100Mb Ethernet link using an unshielded, twisted pair, Cat. 5/5e cable; or dial-up modem. The operator's station can be a standalone unit or it can reside on a local area network (LAN) or wide area network (WAN).

Several manufacturers offer starter systems, based on the number of doors being controlled, with basic packages offered in two- or four-door increments. Starter kits are typically expandable, allowing the system to support up to 32 — and sometimes 64 — secured doors. As a system grows toward capacity, it can usually be upgraded to a larger security management platform produced by the same manufacturer. This is made possible by designing newer systems to be backward compatible, allowing users to take advantage of the most recent technological innovations without having to replace their entire system. Larger systems are normally composed of several intelligent controllers linked to each other via network architecture and to a master controller capable of supporting several PC-based operator workstations. This allows virtually unlimited expansion capabilities, including multi-site monitoring and control functionality.

However, the key element in any access control system, regardless of size or complexity, is the actual software package used by that system. The software and its associated applications provided by specific internal programming supply the many features and functions necessary for the successful security management of any facility.

The power of automation

The software programs driving the majority of available access control systems have a UNIX-based architecture (trademarked, industry-standard computer disk operating system), using either an AIX (IBM proprietary protocol based upon UNIX) or LINUX (an open source or “free” version of UNIX) operating system, which has transformed the access control system from basic intrusion detection to a robust, integrated security management tool. It has become a common practice in the industry for manufacturers to supply even the most modest startup system with a software package that either already provides enhanced access control capabilities or can be easily upgraded in a cost-effective manner (Fig. 1).

Enhanced cardholder management capabilities are among the many advantages afforded by the standard software packages currently offered. Cards or badges can be assigned a priority level, which will either allow or restrict entry to a given area within a facility. Often, this includes control and use of elevators for both access to the elevator cab itself and travel to each specific floor. Additionally, the proper order (in/out) of card usage, known as “anti-pass back” can be enforced, preventing a cardholder from using his badge “out of sequence.”

This is accomplished by using a card reader located on each side of a point of entry or exit, with each reader configured as either “in” or “out.” In order to exit the facility, an individual must first enter, presenting his card or badge for a valid swipe. This prevents him from swiping his card to gain entry, and then holding the door open to allow others to enter behind him, without having their cards read. No one may exit the building without previously recording a valid entry using his own access card that same day or shift.

The same holds true for re-entering the building at a later time. One person cannot swipe his own card, then hold the door open to allow others to exit. Should this occur, the individuals passing through the door and leaving the facility without having their cards read will be unable to re-enter the following day. The anti-pass back function can be programmed as either active or passive. If active, an individual's card is deactivated, and any attempt to use it will result in an alarm with the door remaining locked. The passive mode will unlock the door, but will still report an alarm associated with the violation.

Card or badge readers can also be programmed for occupancy control of an individual area, often called the “two-man rule.” This feature allows readers to maintain a count of the number of people in a certain area at any given time, preventing someone being the sole occupant of a highly secure or restricted area within the facility.

Through software and programming, an access control system's database can be configured to support an unlimited number of time and event schedules, such as allowing doors to be automatically locked or unlocked, card readers to be on- or off-line, or even change an individual cardholder's access status to any given area, based upon the time of day or day of the week.

The on-site creation of custom photo identification cards or badges is another common feature of today's access control systems. Using a compatible color digital camera and printer, a personalized access card with an individual's photograph and signature can be produced in minutes. Each person's signature and likeness resides in the system's database and is available almost instantly for positive identification at any operator workstation. An additional benefit is the ability to track each individual's card swipes for time and attendance purposes, with system data automatically transferred to payroll or human resources for immediate use.

Monitoring and control of the flow of traffic — both in and out of a facility — is not limited to human cardholders. Physical equipment and resources can be imprinted with an industry-standard barcode or magnetic strip, which is automatically scanned by any card reader that is passed within the facility. This allows the access control system to not only pinpoint an item's exact location, but also track and follow that article's movement throughout the building. This asset management and tracking option is a powerful tool for locating lost or misplaced equipment, and is also a compelling anti-theft deterrent.

Integrated applications

The ability to communicate with other life safety systems is one of the more noteworthy features provided by access control platforms. Interfaces with intercom and fire alarm systems, as well as with central stations, are among the many options available today. However, the interface to a video surveillance or closed circuit television system (CCTV) may be the most significant offering (Fig. 2).

Many access control system manufacturers routinely offer interface capabilities to nearly a dozen different commercially available CCTV systems. When linked, the two systems offer almost unlimited potential for life safety applications. Camera call-up is one of the most widely used features. This is accomplished by locating a dedicated CCTV camera at or near a secured door.

When an individual swipes the card reader associated with that door, the camera, through software and programming, automatically zooms in on the person's face, displaying it on the operator workstation's monitor. At the same time, the database is searched and almost instantaneously retrieves the photograph assigned to the specific badge being swiped, presenting a side-by-side on-screen comparison for security personnel responsible for allowing entry to the facility.

Another application of camera call-up commonly used involves linking a dedicated camera to a specific secured point of entry. Should an intruder breach the entry, the camera is called up to immediately zoom in on the individual's facial features, and begin recording the event.

Access control systems have emerged as an integral part of thorough commercial building design, and the ever-changing technology associated with these systems will continue to challenge designers, specifiers, and installers to keep pace with their growing use and development. Keeping abreast of the latest improvements in security management technology will be a critical factor in the choice of appropriate products and their application in future projects.

Shaver holds a NICET Level IV certification in Fire Protection Engineering Technology — Fire Alarm Systems and serves as an engineering associate, CET IV for Stanley Consultants in Muscatine, Iowa.