It is also important when planning a wireless access installation to follow the manufacturer’s recommended distances between devices as closely as possible. Here too, however, keep in mind that every wireless installation has its own set of particular circumstances, and many factors will affect the distance you can place devices apart.
Construction materials in walls, ceilings and floors can all have an effect. Leonard offers some suggestions of things to look for: “Can you identify any potential RF problems, such as metal obstructions or other 900MHz equipment? Obvious obstructions include elevator shafts, metal staircases and metal lockers. However, there are other obstructions that might not be so obvious, including ventilation ducts, metal-clad walls and shielded walls. Verify this with the facility manager. Are these obstructions in your line of sight?”
In some cases, there are ways around obstacles. Repeaters and bridges can sometimes get you from point A to point C, around point B. A repeater takes an incoming signal, amplifies it and sends it back out again, usually on a different frequency. A bridge will take a wireless signal and convert it to hardwire data to send on a standard network.
In some cases, there may be no obstacles blocking the line of sight between two devices, but close proximity to ceilings or walls can still cause problems.
Multipath is a problem that occurs when wireless signals bounce off nearby surfaces too much. Each time one of these signals bounces it gets delayed just a tiny bit. When these multiple “copies” of the original signal arrive at the receiver at different times it tends to confuse the message. Some systems are designed to compensate for multipath, but for the most part make sure you aren’t locating devices or bridges too close to too many hard surfaces.
Again, each manufacturer will have its own best practices for installation. Follow the guidelines carefully.
Big Future Awaits Wireless Access
With all the functionality of a wired access control system and 80- to 90-percent less labor in some cases, wireless access control is taking hold extremely quickly. It can provide opportunities where none existed before.
Much like wireless alarm system components, the wireless access market will continue to grow. As technology speeds up data rates and shrinks hardware, the devices will just get better and smaller.
Having a wireless option for access control can open up many doors (pun intended) in applications that previously may have been overly difficult or even impossible.
MCSE- and CCNA-certified Steve Payne has more than 15 years of industry experience and heads Convergence Consulting, an IP and security solutions consulting firm. Be sure to also read his Integrated Thoughts blog.
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