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.
You might conclude from this that there are no wireless access control players in the traditional access control marketplace, but that is very far from the truth. In the past few years a number of good and competent manufacturers have stepped up to the plate and have begun producing viable wireless devices and systems.
Most of the manufacturers of wireless access control systems started out as niche systems manufacturers, although some of these companies, including Schlage Wyreless Access, Isonas, Brivo, Cypress Computer Systems, Linear Access and SALock, are coming into their own.
Many Applications, Many Options
Dick Burkley, one of the founders of Isonas and the new president of the company, has indicated that the major motivating reason for a wireless access control implementation is the ease of installation; it avoids the labor, time and cost of wiring. Lester LaPierre, marketing manager for Schlage Wyreless Access (Ingersoll-Rand Security Technologies), claimed that wireless installation can take less than one hour at the door, and the existing UL 10C rating on the door remains intact. This could translate to savings of at least 20% in the overall project labor costs because of the improved efficiency of the installation teams.
La Pierre said, “Many traditional system integrators who are more comfortable installing cable-based systems see this new technology as a tremendous threat to their business.” However, the ease of installation of wireless makes it attractive in a number of situations.
• End-to-end wireless solution
• Extension of existing system, often for a new, hard-to-reach location or remote building
• Temporary solution that requires mobility (for instance, if use of a building will be short-term)
• Undercover security application where wires cannot show
• Retrofit application where wire and cable access is a major cost issue
Solutions That Overcome the Odds
Schlage Wyreless Access seems to have overcome some of the perceived limitations of wireless technology. Until recently, connectivity was accomplished via the existing access control field panel through the reader connection ports. Wyreless has found a way to connect directly onto the existing proprietary RS485 bus using a PIM controller with a custom driver for that manufacturer's protocol.
Wyreless' LaPierre said his company's products use 900 MHz transmission because it is license-free and has no conflict with other devices, and it offers better performance and better range than other frequencies. 900 MHz systems are largely oriented for line-of-sight communications, so a detailed site survey is always recommended to prevent blind spots.
One of the unique features of the Wyreless solution is dynamic channel switching, which automatically switches channels when it encounters interference in harsh RF environments.
Wireless on the Network
One of the leading new entrants into the wireless access control market is Isonas, which has taken a totally different approach to wireless access control. In 2001 the company introduced a TCP/IP-based card reader/controller. This network-attached appliance has begun to receive significant acceptance in the marketplace.
In 2005, Isonas attached 802.11b wireless communication capability to this product using a Lantronix OEM WiPort module. The system can be maintained over the existing network by the IT staff using the Isonas Crystal Matrix Software. The 802.11b transmission format allows them to integrate the wireless version of their card reader directly into a customer's existing infrastructure.
Burkley stated that with existing access control systems, the ISONAS solution drives the cost of implementation down since there is no access control panel; every card reader/controller is essentially a network-attached, stand-alone device that is connected to the host PC over the existing network or corporate backbone. Adding the wireless option to the appliance costs about $300.
Using the Isonas package with other existing access control packages does present a couple of challenges. The existing host system will need to have an appropriate driver installed using the Isonas API to allow for the integration of information to and from the system. Isonas has developed a BACnet driver that should make communications with BACnet-based gateway controllers an attractive opportunity.
Security of Transmission
The age-old question of whether wireless transmission can be compromised must also be addressed.
• In the case of 900 MHz communication, the transmission is encrypted with proprietary encoding, thus making it very difficult to get into. One would need to have the exact model of the equipment installed with the exact same setup to attempt a breach, and then one would need to have intimate knowledge of that specific installation in order to try to penetrate it—a very difficult task indeed.
• In the case of proprietary 2.4 GHz communication, the transmission is encrypted with proprietary encoding; thus, the same criteria as for 900 MHz apply
• In the case of IEEE 802.11b/g 2.4 GHz communication, a different set of criteria for security transmission applies. All the normal requirements of 802.11 communications need to be addressed. Point-to-point MAC addressing, 128-bit WAP or WEA encryption must be put in place to provide for a secure environment.
Test Before You Buy
The best way to ensure that you are going to have a successful implementation is to do a test before committing to the project. Most manufacturers have portable test sets for that very purpose, so it is not too hard to take the proposed system for a test drive (admitted on a very small scale) and check out its performance ahead of time.
Want It? Ask for It!
Wireless Access Control is alive and thriving. In the right application it may even be the most cost-effective solution. With the rising cost of labor and shortage of skilled technicians, wireless access control will likely become the solution of choice.
I asked Isonas' Burkley if the major access control manufacturers would move into the wireless market. He replied, “When the end users demand it, then the major companies will be forced to do so.”
Lionel Silverman, PE, is vice president of business development for Facility Robotics Inc., a nationwide system integrator specializing in building automation and security systems for larger multi-location and prestigious clients. He is a member of IEEE and ASIS.