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Bringing merchants the wonders of Wi-Fi

By Tim Cormier

Wi-Fi technology liberates broadband Internet connections by eliminating the costs and delays associated with traditional wire installation. Using Wi-Fi, a merchant with a broadband connection can extend service throughout a location with minimal installation cost and without having to run Ethernet cable from a router to network devices.

Wi-Fi (derived from "wireless fidelity") refers to the underlying technology of wireless local area networks (WLANs). It allows Ethernet data to be transmitted without cables by using standardized radio transmissions in the 2.4GHz public range.

Wireless installations can be done more quickly than cable. They're also less expensive and provide merchants with greater flexibility, including the use of mobile devices within signal range. Wi-Fi is what enables merchants to offer wireless hotspot services.

From simple to sophisticated

Small implementations are generally simple and in many cases can use low-cost, off-the-shelf Wi-Fi hardware from local electronics dealers such as Circuit City and Best Buy. When setting up a Wi-Fi POS system, it's a good idea to conduct or arrange for pre- and post-installation site surveys.

For simple mom-and-pop stores, a quick scan with the wireless network connection feature built into Microsoft Windows XP, or a similar utility that was installed with a Wi-Fi network card, may suffice.

For measuring signal strength and other more robust functions, you can load a freeware network sniffer, such as NetStumbler, onto your laptop or PDA.

More sophisticated installations including WLANs in large malls or entertainment venues (football stadiums, for example) may require multiple wireless access points to ensure uniform Wi-Fi service.

In these cases, you may want to contract with a service company that utilizes sophisticated software to plan optimal antenna locations, analyze wireless interference and monitor performance. If you want to expand your service offerings and capability, a variety of tools are available, priced from a couple hundred to several thousand dollars.

Being able to help fine-tune customer installations is a worthwhile endeavor; there are multiple factors that can impact optimum Wi-Fi performance. One is that Wi-Fi shares the 2.4GHz radio band with other devices. Some cordless phones, Bluetooth devices and microwaves can all transmit in the 2.4 GHz band.

Physical barriers are another common Wi-Fi issue. Walls, doors, floors, walk-in freezers, etc., all have absorptive and reflective properties that impact how a terminal receives a radio signal. Knowing where potential dead spots are will allow you to move transmitters to optimize coverage area.

Sizing up the site

A site survey looks at both the physical and radio frequency (RF) environments and provides an idea of the operating parameters. Recently, VeriFone contracted with Renaissance Network Solutions (RNS) to conduct a site survey for a sophisticated restaurant installation. RNS performed an RF sweep of the restaurant to look for other Wi-Fi signals, rogue devices and interference.

RNS discovered another Wi-Fi signal across the street that impacted the restaurant's car-side POS system. The restaurant switched to an alternate broadcast channel, and the issue was resolved. RNS also evaluated signals from the restaurant's paging system and microwave ovens and determined they would not be a problem.

Signal levels were measured at all points in the restaurant. Based on the equipment and environment, RNS drew a coverage plot showing that the front of the restaurant was subject to weaker coverage, while the signal was strong in areas that didn't need it, including the kitchen.

RNS recommended relocating the access point to the center of the seating area and moving the restaurant's radio to a level above 10 feet. This resulted in stronger signals and greater performance where it was most needed, including in the bar and in the restaurant's corners.

Wi-Fi can be very simple to operate; many consumers have wireless networks in their homes. But as ISOs and merchant level salespeople, it helps to have working knowledge so you can determine whether you have the skills to help merchants successfully operate Wi-Fi, or whether you need to call in experts or acquire more sophisticated tools.

Tim Cormier is a network engineer with VeriFone. E-mail him at

Article published in issue number 060601

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