Avaya has quietly rolled out PBX-extension and seamless inter-network roaming capabilities to its customer base. Unlike other mobile convergence setups that require an appliance for wireless signal handoff and management, Avaya's solution involves installing client software on dual-mode handsets only.

The reason Avaya can boil down its enterprise fixed-mobile convergence (e-FMC) capabilities into client software is that the system is not intended to be PBX-agnostic, says Neil Lewis, Avaya global product manager for Avaya’s one-X Mobile and Extension to Cellular products. In other words, the Avaya one-X Mobile dual-mode software client enables PBX extensions to wireless networks and seamless Wi-Fi-to-GSM cellular roaming only in shops running Avaya SIP Application Server and Avaya Communications Manager IP PBX.

Avaya hopped on the FMC bandwagon early in the game, first notoriously partnering in February 2003 with Motorola and Proxim to build seamless Wi-Fi-to-cellular CPE-based enterprise solutions that required a special handset and signal handoff appliance from Motorola. Avaya is no longer selling Motorola’s FMC appliance, branded the Wireless Services Manager, Lewis says. The Motorola CN620 handset never shipped commercially.

Last summer, Avaya added Communications Manager extensions to cellular and network-to-network communication that required users to push a button on their phones to manually change networks. The roaming function was upgraded to a seamless handover in November.

Lewis says that offers requiring appliances “only add cost to the equation.” On the other hand, those offerings - most notably from start-up Agito Networks, Aruba, DiVitas, FirstHand, and Siemens - are PBX-agnostic, allowing enterprises to mix and match “best of breed” e-FMC solutions and PBXs.

Most e-FMC systems attempt to be somewhat dual-mode-handset independent. Avaya one-X Mobile supports different dual-mode handsets depending on the PBX extension capabilities users want. Basic Avaya desk phone features, such as call transfer, extend to Symbian and Windows Mobile-based devices. Full Avaya unified communications applications run on Research In Motion BlackBerry, Palm, and Java devices. They will also be available for iPhones first quarter 2008, Lewis says.

Joanie Wexler is an independent networking technology writer/editor in Silicon Valley.