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Where Is Wireless Access Control?
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Wireless transmission has long been a subject of technical fascination. Significant advances in wireless burglar alarm systems have made the wired burglar alarm a dinosaur of the security industry. Of late there has also been a sharp increase in the use of wireless connectivity with CCTV systems.
So why not use wireless connectivity for access control applications? Surely wireless communication between the access control panel and readers would offer many benefits. But there's a limited number of serious vendors active in this marketplace. There must be significant reasons for the currently limited use of wireless access control.
Range Limits and the FCC
Wireless connectivity was originally considered to be a solution for cable replacement or elimination. Most manufacturers use ready-made wireless Tx/Rx (transmit-receive) circuit board assemblies for security-related connectivity applications. These devices work in the license-free 900 MHz and 2.4 GHz wireless bands.
The Federal Communication Commission limits the power output of devices that operate in these license-free bands, and limited power can mean limited range. Generally within a building the range is also limited by the steel framing inside the walls. A built-in antenna typically has a range of between 100 and 200 feet. Outside the building, a built-in antenna can typically offer 300 feet. With an external antenna, a range of 1,000 feet is possible, and with a directional Yagi antenna (900 MHz only) you can reach up to five miles.
Most manufacturers use spread spectrum transmission because it provides some data security, and then they add encryption to prevent unauthorized access to the transmitted information.
Some Common Misconceptions
While power and range are legitimate issues, some managers are reluctant to use wireless access control systems because of misconceptions and misunderstandings about what wireless technologies can do. Some examples:
• Wireless is a good solution for only a narrow range of facilities—niche use only
• Wireless communication can be easily compromised
• Wireless communication is expensive
• To install wireless, you'll have to replace your entire existing system
• Concrete and steel make wireless an impossibility
Several Companies Provide Solutions
If you're looking for wireless access control and start your search on Google, you'll find several vendors of wireless computer communications but very little in the area of traditional access control applications. The first page of search results won't include anything on panel-to-reader communication.
