With all the advances in telecommunications over the past 20 years, you'd think the situation would be better than this. Yet office and warehouse workers still don't have phones that work consistently both inside and outside of buildings. International road warriors still juggle different cell phones with different plans, depending on which country they are in. Why can't they have just one handset that can switch between networks as they move about?

The reasons are several, and the answer is complicated. But there are signs that some of the biggest barriers to true fixed-mobile convergence (FMC) are starting to fall.

Vendors have been talking about dual-mode mobile phones -- handsets that can handle cellular calls and also use Wi-Fi networks for VoIP -- for a couple of years. The appeal for business users is better, more consistent mobile phone coverage in office buildings, where most mobile voice traffic occurs, as well as cost savings from using VoIP for free calls, either in the office or at hot spots while traveling.

But solution providers have yet to see many of these handsets on the market. "Everybody is talking about it because it's the Holy Grail of wireless communications," says Russ Johnson, director of technical services at Technology for Education, a Cisco solution provider. "The problem is, there are not enough supported devices."

On the technical side, Wi-Fi requires more power, so battery life can be an issue. Most phones don't have the high-performance processors required to handle a VoIP data stream, resulting in poor call quality. And Wi-Fi LANs aren't always robust enough to handle VoIP and other converged applications, notes Gregg Kalman, vice president of U.S. channels at Meru Networks, a provider of advanced Wi-Fi infrastructure. Unless the network prioritizes latencysensitive applications like voice, the handoff from one Wi-Fi access point to another can be too slow, resulting in jitter, poor call quality and even dropped calls.

A Changing Strategy
The biggest market barrier, however, has been strategic: The main channel for cell phone hardware has had no incentive to push dual-mode phones. In fact, it has good reason to discourage their adoption. "Most businesses buy cell phones through the mobile carrier, not the hardware vendor," says Jessica Tanenhaus, vice president at Mavenspire, a solution provider and businessprocess consulting organization. "And carriers are reluctant to provide hardware that allows people to avoid paying charges to the carrier."

Now that is changing. Experts say that mobile operators are less threatened by Wi-Fi and VoIP than they used to be. In fact, some are starting to embrace FMC. In February T-Mobile, for example, launched consumer trials of home Wi-Fi routers that allow dualmode phones to make VoIP calls. By using Wi-Fi to ensure better and more reliable coverage in homes and offices, carriers hope to encourage customers to rely more on their cell phones and, perhaps, ditch their landlines altogether.

"Although FMC is still in the early stages, it's going to become mainstream," says Frank Terence, category manager of networks, security and mobility at Ingram Micro. "It is moving in that direction."

A major boost to the market is the fact that most major U.S. carriers have launched plans that give users unlimited minutes for a fixed monthly price, says Mark Tauschek, senior research analyst at Info-Tech Research Group. With their revenue model no longer tied to the number of minutes used, Wi-Fi is no longer a threat. In fact, some operators are hoping that VoIP over Wi-Fi could reduce voice traffic on their networks, freeing up capacity for higher-revenue-generating 3G data and multimedia services.

On the hardware side, a handful of companies have introduced or plan to introduce technology that works with a variety of mobile handsets and carriers, breaking the link between hardware and service -- essentially wresting control of the market from the mobile operators, says Tauschek. These companies, which include startups Agito Networks and DiVitas Networks, as well as Cisco Systems, are selling a mobility platform that integrates into a customer's existing IP PBX. Benefits include enhanced mobile coverage in buildings and facilities; integration with corporate PBXes; and cost savings on international cellular calls.

Agito-Cisco Alliance
Agito Networks, founded in 2006 by a group of wireless experts from Cisco, started shipping its product in January 2008. The RoamAnywhere Mobility Router appliance attaches to the enterprise LAN and comes with client software that is loaded onto the phones. The product enables mobile phones to perform many of the functions of a desk phone on the PBX, in addition to enabling the handoff from cellular to Wi-Fi via the corporate network and vice versa, says Pejman Roshan, vice president of marketing and cofounder.

Agito also is providing its FMC technology to Cisco for inclusion in Cisco's 3300 Series Mobility Services Engine, says Roshan. When the product was introduced in May 2008, Cisco said it planned to add fixed-mobile convergence capabilities by the end of the year. That could be a watershed event for the market, says Tauschek. "Once Cisco comes out with it, they'll start flogging it pretty hard," he says. "I think it's definitely going to take off over the next year." He says the availability of dual-mode phones has already started to increase, particularly in highend devices like smartphones. Roshan notes that many BlackBerry, Windows Mobile and Nokia phones now incorporate Wi-Fi. "By 2010-2011," he says, "we expect most business phones will have Wi-Fi."

Waiting for a Break In the FMC Market
Meanwhile, solution providers continue to wait until all the components for FMC come together. Mavenspire's clients -- small and midsize companies with international offices -- could save a lot of money by using dual-mode cell phones, says Tanenhaus. One client has a monthly cell phone bill of $30,000, particularly high because of the expense of calls between its Paris and Tunisia offices, she says. Right now, Mavenspire is helping the company set up a system of arbitrage -- by using particular phones and carrier plans in particular countries -- to reduce those costs. But that doesn't help when people travel. With dual-mode phones, a traveler could use a regional cellular plan when in Paris, but switch to Wi-Fi when in Tunisia, where cell phone charges are astronomical.

Johnson doesn't expect to see much change in the market until the carriers are ready and committed to making the transition, and he thinks it's still too early for that. "Not all their service areas support 3G," he says. "They are trying to figure out how to generate additional revenue, and the only way they can do that is through value-added services on their 3G networks."

Meanwhile, he's preparing his clients for that day. He makes sure their Wi-Fi infrastructure is complete and robust. He encourages them to upgrade to the latest version of Cisco's unified communications platform. "That way," he says, "when devices do come out, they'll be supported by the systems we are putting in today."