Despite the hype surrounding VoIP and the technology's proven benefits, some organizations are still taking baby steps toward converged networking.

One such outfit is Baptist Health Medical Center in Little Rock, Ark., which has 8,000 phones, but only 240 IP ones. (Compare IP Phones.)

"I just can't see us going up on one floor and saying we're taking out all of the TDM phones and putting in IP," says John Myers, convergence analyst at the medical center. "To go in and change everything out just to be changing it just doesn't make sense."

That's even though Myers is well aware of what VoIP promises: a converged, cost-efficient infrastructure and new productivity-increasing applications. There are no shortage of early adopters, from Bank of America to Black and Decker, which llaud the benefits of VoIP and unified communications.

The trends are clear: In 2007, IP PBX revenue grew 29% to $1.6 billion and line shipments grew 32%, according to Dell'Oro Group. Dell'Oro expects IP lines to surpass digital and analog PBX lines for the first time by year-end. By contrast, TDM PBX revenue declined 20% to about $1 billion in 2007, Dell'Oro found.

Still, Baptist Health says a measured transition to VoIP makes the most sense for it, and there are lessons to be learned from its approach.

Most of Baptist Health's 8,000 phones are located in a 15-floor building in Little Rock, but the medical center has eight sites overall. As it moves offices or builds new facilities, it will outfit those desktops with IP phones, Myers says.

"We never made a decision to forklift everything out and replace it with IP, but as departments moved or are added or if we buy up a clinic across town – if we feel it's a good candidate for IP that's what we do," he says.

Baptist Health's slow move to VoIP began with a 15-phone trial two years ago. The medical center is predominantly a Nortel shop and it deploys the vendor's Communications Server 1000 IP PBXes and 1140E IP phones, as well as its analog and digital PBXes and phones.

The hospital embarked on its VoIP quest in an effort to reduce cost. Myers figures the medical center can save money on expense of cabling new facilities by running voice over the IP data network instead of nailing up a separate voice network every time a department moves or is added.