You don't have to fly the shuttle daily to live in Boston and work in New York. Instead you might hook up to your office via a computer, as Catherine Marenghi, a writer for a consulting firm, does.

In Alexandria, translator Michael Barjansky taps out technical material on a computer for his employer in Maryland -- avoiding hour-plus commutes each way.

And in St. Louis, U.S. Army officials say telecommuting has increased programmers' productivity and reduced costs.

Several hundred U.S. employers are letting their employes "telecommute" -- regularly work at home and link up with the office via computers and phones. Among them: Blue Cross and Blue Shield in Columbia, S.C.; the Rising Star software company in Torrance, Calif.; F International, a multinational consulting firm in Tarrytown, N.Y.; and a Visa credit card branch office in Phoenix.

Jack Nilles, who coined the term "telecommuting," says that as many as 30,000 Americans may be telecommuting, if those doing so part-time are included. Nilles, director of the international technology program at the University of Southern California's Center for Futures Research, says 10 million Americans may telecommute by 1990.

The term telecommuters, according to Nilles, includes both computer-users and people employing the phone for work normally done in person. With or without a computer, however, there are pitfalls: Will you lose out at promotion time? Can the boss comfortably manage you without seeing you? Can he judge you according to the work you've turned out? Can your company's computer system easily accept material from other machines via phone? Are your coworkers savvy about computers? What reference materials do you need on the job? How about working at the office on some days and at home on others? Are you a self-starter? Skeptics worry that the wrong people in the worst cases can turn into lazy beer-drinkers lounging around in blue jeans.

"It's a hell of a life," says a Washington lawyer -- baffled that some people could survive without the companionship of office workers.

Catherine Marenghi, however, has been happily telecommuting for 2 1/2 years.

The 30-year-old Tufts English graduate was working in the Boston area for a trade newspaper when the New York offer came.

"I don't like New York -- the pace, the noise, the living expenses," she said by phone from her one-bedroom condominium, "and I have friends and family here."

So she talked her boss, John Diebold, a well-known consultant, into hiring her as a telecommuter.

She now "mails" in book chapters and articles and speeches. "I couldn't get much writing done at the office," recalled Marenghi about her days at the trade paper. "There were too many interruptions, too much chatter."

Like many telecommuters, however, she seeks out companionship by lunching out with friends.

In addition, Marenghi flies to New York every two weeks for face-to-face meetings. And she keeps up with company business through phone calls; experts emphasize the need for bosses and colleagues to speak to telecommuters, not just key to them.

Marenghi, who maintains regular business hours at home, advises telecommuting prospects to "separate your work space from the rest of your home, even if it's just a closet."

For technical help beyond a sales rep's, go to a computer club and work closely with your company's data processing department -- or use a consultant. Beware, however, of many pros' bias in favor of more expensive equipment.

In Alexandria, Michael Barjansky receives telexes from the Singer Co.'s Link Simulation Systems Division in Columbia. The part-time Singer employe works with both telexed and regular material; among other things, he translates German technical specs (for power plants) into English.

"My computer and communications make everything much easier and, in fact, more interesting," says Barjansky, a retired foreign service officer. Singer sends material to him via the old telex network. MCI Mail, an electronic mail service, converts the telexes into a format that Barjansky's computer can understand and whizzes the results to him over the phone lines. Frequently, services such as MCI, CompuServe and The Source can help bridge technical differences between machines -- although the home worker may not enjoy such niceties as underlining in computer-transmitted reports. Computer users may encounter such problems even in normal offices.

"When I get a message from Singer to translate," says Barjansky, "I can use a split screen on my computer. I can type the translation on the bottom while I read the original from the top."

And if the material isn't in telex format or the documents aren't too long, Singer loads them into a facsimile machine for Barjansky to receive on a reconditioned model "dex 1100" made by Burroughs that he bought for $300. The material takes three minutes a page to transmit.

Other telecommuters use microfilm and microfiche to retrieve materials needed for reference, or, as Barjansky does on occasion, make trips to the office. One big advantage of telecommuting for Barjansky: He needn't lug around his usual pile of dictionaries.

Some hidden costs pop up, however. Barjansky requires two phone lines, for instance, to talk and receive computer messages simultaneously.

Another reason for two lines: to keep business and personal life separate, according to one home work expert.

Challenges notwithstanding, most telecommuters thrive on their new-found freedom. "I'm saving gas, dressing in comfortable grubbies when I write," a successful, productive telecommuter said, "and with the direct connection I can prove that I'm working. My computer is really paying off."