Peterson's comments, delivered in a keynote address to most of the 5,000 conference attendees, stood in stark contrast to several presentations from representatives of businesses well on the way to outfitting their companies with new networks, phones and applications based on IP who said they've already saved money.

Some of those IT managers have reported millions of dollars in annual savings, thanks to reductions in long-distance call costs and a decrease in the amount of work for IT staffers who have to add or move phones. Other savings resulted from deploying only one data line to a desktop without the need for a separate costly voice cable.

"We don't believe IP telephony is a cost-reduction case," Peterson said in his speech. "I fundamentally believe that the real value is not cost reduction, but how it changes the business."

Peterson was not available to elaborate on his comments later, but Jorge Blanco, Avaya's vice president of strategic marketing, said recent independent research and customer surveys have raised questions about earlier assertions of VOIP cost savings. As more systems have been rolled out, the return on investment issue is being clarified, he said.

"Don is trying to make a reality check in his comments," Blanco said. "There are operational and cost reductions, but we're trying to say don't go at this through the lens of saving money. Instead, lay the foundation to drive business strategy."