Research in Motion has outfitted its widely heralded BlackBerry messaging device with some basic fixed-mobile convergence capabilities.

The company last week introduced the BlackBerry Mobile Voice System (MVS), which allows enterprises to integrate cellular-enabled BlackBerry models with user desk phones and corporate PBXs. Users can manage calls and access corporate directories through their familiar BlackBerry interface and menus.

Employees get a single business phone number to call, but users can have multiple wired and wireless phones ring simultaneously to avoid voicemail pileups and telephone tag. Enabling one number to concurrently connect to multiple devices is sometimes called “twinning.”

Twinning is a simple first step toward FMC, which will eventually unite various mobile and fixed networks with seamless inter-network voice handoffs, presence functions indicating user availability, unified messaging and other collaborative communications that span network borders.

As yet, though, no BlackBerry devices support both cellular and Wi-Fi communications. Rather, there is an 802.11b Wi-Fi-only enabled device (the 7270), as well as a number of GSM or CDMA cellular-enabled devices.

Also, “there is no presence or unified messaging supported at this time” in the BlackBerry MVS, said David Heit, RIM director of enterprise product management. “But you might expect to see presence, now available for instant messaging [on the BlackBerry], evolve to include a voice element.”

According to Heit, user requirements to blend BlackBerry with the corporate PBX are the following:

* You must be running the RIM BlackBerry Enterprise Server (BES) minimum software Version 4.1.2.
* You must be running Ascendent Systems’ voice mobility server. RIM acquired Ascendent, which has long offered twinning services to many phones, last year.
* You must install a PBX connector piece of software onto the Ascendent voice server.

In a similar vein, Cisco in March launched its Unified Mobile Communicator, which provides employees with cellular access to their enterprise PBXs, directories, unified messaging, and conferencing services from a diverse set of mobile and smart phones. Unified Mobile Communicator uses technology gained when Cisco acquired Orative last fall. It supports BlackBerry cellular-enabled phones as well as mobile phones running the Symbian, Windows Mobile and BREW operating systems.

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