Imagine being on a Hawaii vacation and stepping onto the hotel balcony to watch the sun rise over the Pacific.

Then the phone rings. It's a co-worker from the mainland. Ready for the conference call?

It happened to Darlene Frudakis, president of PetAg Inc., a pet food maker based in Hampshire, Ill. Even more surprising was Frudakis' reaction.

"It was just a fabulous feeling," said Frudakis, a full-time telecommuter who is very comfortable blurring the line between work and play. She relishes the "freedom and creativity . . . to think outside the box" that comes with being physically detached from her company's headquarters — whether that is at home in Novato, Calif., or on vacation — and says that makes her more productive.

Still, there is a downside to a lifestyle in which the "office" is really a state of mind: "You can't leave," she said.

More than 30 years after the lifestyle began inching into mainstream corporate culture, and in spite of the potential pitfalls, there were almost 14 million Americans telecommuting at least part time in 2004, and an additional 7 million running businesses from home, according to the most recent Labor Department data. That's up marginally from 2001, but human resources experts believe the number will continue to climb because more workers are demanding flexibility, and because high-speed Internet connections make it easier than ever to ensure a close-knit relationship between telecommuters and their colleagues and clients.

In 2005, 44 percent of U.S. companies offered at least some telecommuting options, according to a survey of 1,043 large employers by Mercer Human Resources Consulting. That is up from 32 percent in 2001.

In the post-9/11 era, corporate America views a work force that can function remotely as a strategic advantage, experts said.

"The reason I think it's gaining momentum is because of natural-disaster preparedness," said Ellen Galinsky, president of the New York-based Families and Work Institute, a nonprofit that researches work force trends for corporations. Galinsky said it was the less centralized companies that were up and running fastest in the days following the Sept. 11 terrorist attacks.

Maryella Gockel, who oversees flexible work scheduling at Ernst & Young in New York, believes it is still the employees who are driving the trend. At first the telecommuting bandwagon was led by new mothers who wanted to have more time with their children, she said. Then dads sought similar arrangements. And, finally, employees without children began requesting the same kind of scheduling options their co-workers were receiving — they wanted to devote more time to a hobby or just spend less time in traffic.