Said Raikes: "Workers today struggle with too much communication in too many places." He noted that they have office and home-office phone numbers, fax numbers, cellular phone numbers, IM accounts and e-mail addresses and that "they want more control over the communications."

He said Microsoft's vision for unified communications will be software-based and recognize the need to integrate PCs with desktop phones for functions such as recognizing a person's "presence" or availability. Presence can be indicated, for instance, by the ability to see an icon for someone working in a remote location who is available for contact through voice, e-mail, IM or other modes.

"It's a win-win for both companies," said Zeus Kerravala, an analyst at Yankee Group Inc. in Boston. "Microsoft understands the user experience, and Nortel understands voice and networks. So they'll be merging the desktop experience with traditional telephony.

"Microsoft has a definite monopoly on the desktop," he said, "but historically, you can question their software quality. Nortel is a very good communications and engineering company, and the combination of the two works to both companies' strengths."