Choosing a wireless electronic access control solution

Selecting the best electronic access control system requires careful planning, a solid technical evaluation process, a well-defined scope of work, selecting an experienced contractor and proper execution.

Any electronic access control system installation project requires that many different aspects of the project's scope - technology used and operation - be decided based on a holistic solution that includes the environment and culture of the organization that will ultimately be using the technology.

The goal is an access control system that will allow authorized access, deny unauthorized access and be easy for the users to operate. This sounds simple, but it is not a cut-and-dry, obvious process. There is not a perfect product for a project, nor is there a perfect technology.

Many times a product or technology is forced to be the solution by management or a department within a company and the best solution is consequently not selected, because of a bias or lack of information. This approach of evaluating all aspects of an access control project is more difficult and time-consuming, but it provides the best results.

To help illustrate the importance of evaluating all aspects of an electronic access control project in an application and expand on the idea of a "best solution," we will take a look at one topic in the decision process: choosing to use wireless technology in an electronic access control solution.

Why Go Wireless?

Wireless solutions have gained in popularity, and nearly any security function - including electronic access control - can be processed via a wireless technology. There are many reasons to incorporate wireless technology in security - the most obvious being the elimination of wiring. For example, the wiring needed to connect the reader to a data gathering or control panel is eliminated in networked access control systems. Because wiring is minimized, the ease of installing a wireless system in existing buildings with limited access to a wired infrastructure is a natural.

A second reason is the ease of retrofitting electronic access control in existing buildings or facilities. The replacement of door handle/locking hardware can be addressed with a wireless electronic access controlled reader/mechanism. There are specific applications where this advantage is important and has been the primary focus for wireless electronic access control systems. They include schools and universities, hospitals, hotels, apartment complexes, elevators, exterior portals and bathrooms within a facility.

Wireless Configurations

Wireless electronic access control systems come in a variety of configurations. A card reader is normally part of the door locking/release mechanism. These devices use proximity technology for the most part, although other technologies are also available. There are also Radio Frequency (RF) key fobs that can activate the door locking mechanism similar to a garage door opener.

Some wireless electronic access control systems use WiFi network standards, such as 802.11, to communicate; while some use various radio frequencies, such as 900MHZ or 2.4GHZ.

The number of users that have access to a given door reader/mechanism will vary tremendously as well as any tracking of users access via the door reader/mechanism.

There are many configurations and variations that all fall under the "wireless" electronic access control umbrella. To control the complexity of this discussion, the topic will be addressed considering there to be basically two types of wireless electronic access control systems: networked and standalone.

Networked Wireless Access Control

A networked wireless access control system is often linked together via data-gathering panels to a central computer or computers. The data-gathering panels can communicate to a central computer over a wired system that can be IP-based.

The reader/mechanism, at the controlled door, will normally hold a given number of card numbers (usually around 2,000) and will retain a set number of transactions in "First-In First-Out" (FIFO) memory (usually in the 10,000 range).

The reader is incorporated into the door handle/release mechanism, allowing the door mechanism to control access as well as limit access to authorized cardholders only. The door mechanism can also time stamp the cards that were allowed and denied since the last communication with the data-gathering panel.

The wireless communication from the reader to the data-gathering panel can be 802.11, which would be ideal for an IP-based electronic access control system. This communication can also be encrypted.

In the IP-based architecture, a WiFi node would communicate to the door reader/mechanism and then communicate to a central computer. The wireless door reader/mechanism is based on open architecture, using the existing network standard.

The advantage to this system is its ability to connect to an existing WiFi network. For this type of application to work well for the Security department, a solid working relationship would need to exist or be developed with the Information Technology (IT) department.

In the data-gathering panel example above, the door reader mechanism could communicate to an RF receiver that would connect to the data-gathering panel. This approach could use a WiFi receiver or a radio receiver on another frequency; however, a protocol must exist that allows the data-gathering panel to understand the data it receives from the door reader/mechanism. Many door reader/mechanism manufacturers have made agreements with the manufacturers of electronic access control systems that incorporate data-gathering panels to allow proper communications. The actual card data is normally Weigand protocol, but the other communications required to process and modify the memory within the door reader/mechanism will be proprietary to the data-gathering manufacturer.

A final advantage of a networked wireless electronic access control system is that the door reader/mechanism can operate in a standalone mode until communications is desired or reestablished, if lost. The communication is normally "real-time" or on a set interval. The door reader/mechanism uses battery backup to enable transmissions to a receiver either at the data-gathering panel or on a WiFi node while retaining the access transactions on a FIFO memory located in the door reader/mechanism. The battery backup is in the form of commercially available standard configuration batteries, such as AA (6ea.). The electronics in the door reader/mechanism is designed for minimal current draw, thus allowing batteries to last an extended period of time. The actual battery life will depend upon the number of door releases, communications back to the data gathering panel/WIFI node and updates from the central computer. A rough time estimate for battery life would be in the 18-month range for a door reader/mechanism with "average" usage.

The door reader/mechanism also reports battery status back through the receiver to notify maintenance personnel of its status. The battery replacement usually requires a special type of wrench and access to the secure side of the protected area. In high-traffic areas, a power supply can be added to eliminate any battery replacement issues (requires some additional wiring).

Standalone Wireless Access Control

In a standalone wireless access control system, each portal or door is controlled by a door reader/mechanism that can hold many card numbers and can store transactions, similar to the centralized/network door reader/mechanisms discussed earlier. The primary difference is that the standalone reader does not communicate to a data-gathering panel or WiFi node. This unit will transmit the transactions and modify card numbers via a wireless link directly to a computer in close proximity to the reader; or, it can sometimes modify the user card numbers with specially coded cards.

The advantage of a standalone system is that it can be installed virtually anywhere without regard to communication infrastructure. Remote sites or retrofits are ideal applications for this type of system. The door reader/mechanism is installed, updated and put into operation and can be left alone except when an access/denial report is desired or when card numbers need to be added or deleted in the device. The door reader/mechanism normally replaces the existing lock and key hardware.

Both networked and standalone door reader/mechanisms are often Grade 1 locks -high-strength locks for high-traffic areas. They are available in both cylindrical or mortise configurations, and the card reader inside the door mechanism is typically proximity technology. In the near future, smart card technology will be more widely available. Additionally, the door reader/mechanisms are available in different finishes and configurations to address aesthetic concerns.

Installation Concerns

Installation problems for the door reader/mechanism in both types of systems are common. For example, wires can be pinched or shorted when the device is installed improperly. To address this issue, door reader/mechanism manufacturers require certification training.

Issues that typically arise when installing networked wireless access control systems have, for the most part, been based on the problems associated with the network itself. There can be issues related to the installation of the WiFi nodes, receivers at the data-gathering panels, programming the panels or nodes and wireless transmission issues that have nothing to do with the actual wireless access control door reader/mechanism itself. For example the distance between the door reader/mechanism might be to far away from the receiving device for the wireless signal to reliably communicate; or, the wireless door reader/mechanism might be placed close to a source of Radio Frequency (RF) noise that interferes with the transmitted signal.

A manufacturer-trained certified technician would be aware of the types of RF problems that can negatively affect the wireless unit.

Also a good practice before installing a number of the wireless door reader/mechanisms is to pick a typical location and verify reliable wireless communication. The manufacturer's sales material may indicate a distance of, for example, 300 feet. This distance is based on "free air space" - which does not guarantee that distance in a specific environment. Medal studs in sheet rocked walls, HVAC ductwork, etc. will affect the distance the wireless signal will travel.

Choosing the best locations to incorporate an electronic access control door system requires a holistic view of the desired access control systems operation, maintenance and system usage. A well-designed and installed electronic access control system needs to appear seamless to the end-users while providing solid security.

Choosing a wireless electronic access control door reader/mechanism requires some study of the products available and establishing a need to use a wireless device. Not only is it important to consider which device is most aesthetic and where it might be used, but issues of updating card holders, receiving access logs, replacing batteries, incorporating these devices into a larger system and the users potential issues/benefits are all part of the evaluation process.

Robert Pearson holds a BSEE and is a Registered Professional Engineer. He has been an instructor at George Washington University teaching "Integrated Security Systems" and "Corporate Security Management," has written numerous articles for various technical magazines and has recently published a book entitled "Electronic Security Systems." On a day-to-day basis he oversees design, project management, and maintenance of security systems for multiple sites. Mr. Pearson is a member of A/E National Standing Council for ASIS International.