Cisco is planning to use Motorola handsets in a converged voice system that will let users roam seamlessly between Wi-Fi networks and cellular phone services.

"The dual-mode phone will be an extension of internal telephone system," said Tim Stone, IP communications marketing manager for Cisco EMEA. "You can make a phone call inside the campus without paying a GSM call charge, and the mobile phone will give you features you get from a PBX extension."

The system, to be delivered in early 2006, will use Motorola dual-mode handsets, and Cisco's CallManager IP communication system for the PBX functions. It will also use Motorola's Wireless Services Manager to provide a seamless hand-over between the two networks.

The system will be sold in partnership with a mobile operator, that will provide the cellular service. Although Cisco has not yet announced any partners, this system will presumably be a contender for the business grade version, due next year, of BT's converged Fusion service.

"This will give mobile operators an opportunity to move into selling enterprise wide contracts," said Stone (along the line we discuss in Mobile operators wield converged phones against the landline). "It will also gives opportunities for IT staff to have closer management of mobile devices and bills."

Early deployments will be in the US, but Cisco plans to launch it swiftly in Europe and Asia, said Stone. The announcement complements an earlier announcement with Nokia to offer simliar systems based on Nokia's Series 60 Symbian phones, which might be more popular in Europe, according to Stone. The Nokia-based offering would have to use an alternative to Motorola's WSM for seamless handoff.

Cisco has shipped around 5 million wired IP phones, and has launched its own Wi-Fi only IP handset, which now makes up around three or four percent of Cisco's IP phone shipments, according to Stone.

Cisco considers it important to roaming individual calls between cellular and Wi-Fi networks, even though NTT has been making large converged voice deals such as announcement with Osaka Gas with a system that can manage a "hard handover" (ie hang up and redial when you roam). Proponents of hard handover systems point out that very few calls are actually made while passing through the office door.

Next year's Cisco system will still have the limitation that only calls of which one end is within the company can roam - so an external calls made on the mobile network, while outside the office cannot roam onto the Wi-Fi network if the user is still connected when he or she returns to the office.

The system will also address other main drawback of Wi-Fi telephony - battery life - and Stone expects to offer a talk time of three hours and a standby time of 50 to 80 hours for Wi-Fi usage. The issue will be addressed by lower-power Wi-Fi silicon, but also by having a voice-grade Wi-Fi network, he explained. "The base stations should not be spaced too far apart," said Stone - as Wi-Fi's power requirements go up with distance. "We can dramatically improve battery life by engineering wireless network properly."

"This opens up a whole range of really exciting possibilities," said Stone. "Phones will support calendaring, e-mail, and intranet applications, all consolidated onto one device."