Dueling Handsets
The next challenge is to choose handsets. Dual-mode devices add a Wi-Fi radio to the GSM or CDMA radios found in normal cellular phones. In the same way that VoIP phones connect to the PBX over the corporate LAN, a dual-mode device uses the company's Wi-Fi network. Advantages include single-number access to mobile workers, single-device convergence, unified voicemail, lower cellular minute usage as calls in the office terminate over the WLAN rather than the cellular network, and a remedy for poor indoor cellular coverage.
Challenges remain as well: Device selection is limited, integration can be difficult, and savings on cellular minutes are too often gobbled up by expensive handsets; see "What'll All This Cost?". And how many of your workers really need this level of mobility? Sixty percent of respondents to our reader survey said cellular phones are provided to a very limited number of their companies' employees; for more on the results of our reader poll, see nwcanalytics.com.
Indeed, despite the hubbub around VoWLAN, unit and dollar sales of both single- and dual-mode phones remain modest. To put it in perspective, Nintendo's Wii and Sony's PlayStation 3 moved more units just this past Christmas than there've been single-mode Vo-Fi phone sales--ever.
Hey, there's nowhere to go but up. Dual-mode handsets like Nokia's E61 and HP's iPaq hw6940 have come on strong, capturing the imaginations of consumers and enterprises alike. Apple's new iPhone will only further that momentum. The MMC (mobile/mobile convergence) and FMC (fixed/mobile convergence) arenas are gaining traction at home and in the office, as evidenced by trials such as T-Mobile's HotSpot@Home and products from DiVitas Networks; find our take on FMC at nwcreports.com.
Some dual-mode phones are designed to use Wi-Fi for data only, but if the device runs the appropriate OSs, third-party applications, such as SIP clients or Skype, can be installed. Other dual-mode handsets, such as the Motorola A910, use their Wi-Fi connections for UMA (Unlicensed Mobile Access), which enables tunneling into the GSM-standard cellular network over Wi-Fi.
Whichever device you choose, continued healthy growth depends on organizations building out WLANs that can actually support Vo-Fi. Our advice? Short term, resist the siren's call of dual-mode where single-mode will do. Manufacturers of dual-mode phones cut their teeth on consumer-grade cellular handsets; they lack single-mode vendors' enterprise experience. Single-mode Vo-Fi phones are much less expensive to purchase, deploy and support and work well for companies that require mobility for employees who predominately stay within range of the company WLAN. Dual-mode phones will be appropriate for those who have company-issued cell phones but could benefit from perks like access to enterprise directories, presence and mobility inside the office. You'll also save on service costs and gain better coverage.
Longer term, as standards develop, dual-mode phones that provide transparent roaming will find broad acceptance in enterprises and homes. Motorola, Nokia and others are working with enterprise WLAN players, such as Cisco, so integration should improve (see "Cisco, Nokia Team on FMC").
