A mobile phone system being developed jointly by Motorola, Proxim and Avaya is designed to help enterprises resolve issues such as in-building coverage and — ultimately — the need for traditional desktop phones.

Dubbed the “enterprise phone,” the system is designed to let users communicate with a mobile device through a cellular network or an enterprise's Wi-Fi network and allow seamless transitions between the two. As result, a person in a building could begin a phone conversation using a Wi-Fi connection to access the enterprise's IP network but walk outside and continue the conversation over a cellular network.

The system allows individual users to move untethered from their desks and enables them to be contacted via a single phone number and requires them to monitor only one voicemail box. For the enterprise, the solution lets it maximize its IP infrastructure while reducing cellular airtime used by employees.

On the surface, the reduced cellular minutes might make the system seem like a bad deal for the cellular company. But Motorola director of marketing Bob Duerr said carriers' initial concerns are offset by opportunities to provide feature-rich voice and data bundles to their customers.

“We've seen all carriers say, “You're taking away my minutes,'” Duerr said. “But when they look at the big picture, they're pretty positive about it.”

Ben Gibson, Proxim's vice president of corporate marketing, echoed this sentiment, noting that an enterprise phone solution increases customer “stickiness” to a carrier. In addition to letting employees access an enterprise's IP network from a variety locations, eventually the enterprise may be able to discard its desktop phones.

Another benefit is that the system will provide opportunities to provide in-building mobile phone coverage, even in hard-to-reach areas such as basements, Duerr said.

“We've trialed it inside our own building,” Duerr said. “It makes life so much easier. You don't have to head for a window every time you get a call.”

This characteristic eventually may be leveraged in other ways. For example, lackluster in-building coverage in high-rises and basements is a recurring problem for public-safety personnel trying to communicate. Gibson noted it is possible to design an enterprise phone system in a manner that provides dedicated channels to public safety when in-building coverage is lacking. Duerr said Motorola's public-safety division already has inquired about the possibility.

Initial versions of the enterprise phone system will require Wi-Fi networks using 802.11a, which is supported by most enterprise-level Wi-Fi systems, Gibson said. Complete systems featuring Avaya/Proxim switching infrastructure and Motorola handsets are expected to be available late in the summer or early in the fall. Duerr said Avaya will market the system to carriers beginning this fall, with carriers offering it to enterprise customers shortly thereafter.

Gibson said one of the challenges faced in developing the system was the fact that Wi-Fi access points typically “ping” mobile devices to check for their availability, a process that threatened to drastically reduce the battery life of enterprise phones. To resolve the problem, designers decided to reverse the system, so the mobile devices will “ping” to test the availability of access points on an as-needed basis.

Currently targeted to serve enterprises, Gibson and Duerr said they eventually see the system becoming attractive to consumers, particularly after WiMAX technology matures.

“I think you'll see businesses use this in the near future, then their telecommuters will use it at home, and it will go from there,” Duerr said.