It helps print U.S. passports, and this week it will play a key role in printing a new national newspaper, USA Today.

It coordinates the work of construction crews on the Alaska oil pipeline.

Its computer programs help New York City's offtrack betting system calculate ticket sales, the posting of odds and the payouts.

Its consultants are helping the Air Force redesign its inventory control system.

What is this omnipresent concern?

It's Continental Telecom Inc., the nation's fourth-largest telephone company, whose ever-growing subsidiaries are supplying technical know-how to a host of companies across the country.

This diversity represents a sharp change for the 21-year-old company that until recently had a reputation as the most rural-oriented telephone company in America. But the turnabout is not without its detractors on Wall Street, who fear that the company's aggressive investment practices may come back to haunt Continental.

Having concluded that the future of local telephone companies is "dim" and "boring," Continental Chairman Charles Wohlstetter set out on a buying spree, acquiring company after company to make Continental a "not so plain and old telephone company anymore."

"We're growing like a baby elephant," says Wohlstetter, proceeding to list the dozen firms Continental has bought or created in the past three years.

Perhaps more than any other area in the country, this growth is being felt here, where the Atlanta-based company has bought locally based companies or located new subsidiaries.

This month, for example, Continental completed its $24 million acquisition of the Rockville-based STSC Inc., which provides remote computer services to 750 businesses, including more than 100 of the nation's 1,000 largest companies.

Also this month in Manassas, Continental's new subsidiary, ConTelVision, begins its first and only electronic-publishing experiment. (For details see story on page 25.)

Continental's presence is felt in many other ways around the metropolitan area:

* With Fairchild Industries, Continental owns half of American Satellite Co., located in Germantown, Md. Using satellites and a widespread network of Earth stations, AmSat provides private telecommunications networks for 250 clients who send data to many different parts of the country. Gannett Co. Inc. will use AmSat's satellite network to print its USA Today newspaper in 15 cities.

* Continental also holds a 25 percent interest in Space Communications Co., a Gaithersburg company known as Spacecom whose prime task has been to design, develop, launch and operate a satellite tracking system for the National Aeronautics and Space Administration.

* The company's year-old international engineering, construction and consulting subsidiary, Continental Page Inc. -- created after Continental acquired units of Page Communications Engineers Inc. -- has division offices in Vienna, with some 300 employes. This subsidiary has built and now operates private telecommunication networks for several Middle East, African and South American countries, for many U.S. airports and for the Alaskan oil pipeline.

* Contel Information Systems Inc., another new subsidiary created out of several mergers -- has two of its four divisions here to provide independent consulting in telecommunications and data processing. One of these, the Government Systems Division in Vienna, is engaged in a multiyear effort to upgrade the Air Force's material procurement system.

* Continental's Executone Inc., which markets a variety of telephone equipment for businesses across the country, employs 260 salesman in the Washington area.

On top of these concerns, Continental maintains its longtime presence in Virginia, serving more than 210,000 telephone customers -- of which more than a quarter are located in suburbs such as Manassas, Dale City and Woodbridge.

In total, Continental contributes to the paychecks of more than 2,300 employes in the metropolitan area.

The company's growing presence here "comes about because Washington has become quite a communications center," Malcolm Holmes, Continental vice's president for finance, explained.

And Continental, no longer content to be just a local telephone company, is taking advantage of the many companies here to expand and offer almost any type of telecommunications technology available.

A local telephone company has a "very dim future," Wohlstetter said. Thanks to competition and the scheduled divestiture of American Telephone & Telegraph Co., he said, "You're now a target for people who want to nibble away at pieces of your business."

"You'd have to be awfully stupid" to want to remain just a local telephone company whose revenues and profits would be regulated by state utility commissioners and whose entrepeneurial efforts would be limited, he added.

"I just couldn't be in a business myself where I knew on Jan. 2 exactly what I would be doing in terms of revenues and profits by the end of the year. That is completely out of consonance with everything else I have done in my life," said Wohlstetter, 72, a self-described "reconstructed capitalist tool."

It was precisely his desire to be a capitalistic risk-taker that prompted Wohlstetter and two partners to launch Continental in 1961. Begun with an investment of $1.5 million, the company now has assets totalling more than $3.5 billion.

With 2.1 million customers in 37 states and the Caribbean, its revenues last year totaled nearly $1.6 billion, its profits $144 million.

"We proved that the old telephone philosophy was wrong. We disproved the old saw which said you couldn't operate widely dispersed telephone companies by a centralized force," Wohlstetter said.

Continental is the product of more than 700 corporate acquisitions, the bulk of which have been small independent telephone companies. In the mid-1960s, officers of these companies were eager to sell, either because there was no one in the generally family-owned businesses who wanted to continue operating them or because they didn't want to spend the large sums needed to upgrade their telephone system.

When Wohlstetter learned that a company was for sale, he would immediately fly to that company's headquarters in his own plane and, if he liked what he saw, make a prompt offer.

In Virginia, Continental acquired 19 companies, making the state its largest in terms of customers.

But as Virginia residents discovered, this aggressive acquisition policy brought many problems because Continental could not spend money fast enough to modernize the telephone system. As a result, service deteriorated significantly, prompting hundreds of complaints. Two years ago, the complaints were so numerous that the Virginia State Corporation Commission ordered $600,000 to be withheld from an approved $4.2 million rate increase pending an improvement in service.

To overcome these problems, Continental has spent $250 million in the past five years to modernize. Stephen Jones, Continental's vice president in charge of this region, boasts that "Virginia has the best service operations of all our service areas." State officials say that Continental customers have one of Virginia's most advanced telephone systems.

This improvement has been reflected by a sharp drop in complaints. According to the company's own figures, the State Corporation Commission received 700 complaints against Continental in 1980. Last year, that had dropped to 455; for the first seven months of this year, the number totaled only 89.

Given this sharp decrease in complaints, Continental officials are now confident they will encounter little opposition to their request to increase local rates by 22 percent. A hearing on this proposal is scheduled for next month.

Now Continental is venturing into the unregulated parts of the telecommunications business.

"We know exactly what we want," Wohlstetter said. After a detailed study of where the company should be, officials have concluded that Continental should focus on selling its equipment and services to small companies or divisions of corporations.

"If we enter the larger end of the spectrum, we'll have competition from some very formidable people, such as IBM, Xerox and American Telephone & Telegraph Co.," explained James L. Robb, executive vice president in charge of Continental's unregulated operations.

Having decided the type of business to go after, Continental drew up a "matrix" to see what companies it needed to acquire so it could provide, in Robb's words, "a small, totally integrated network inside a single building or a large network that could expand [across] the globe." ontinental then adopted a strategy similar to the one it used in acquiring local telephone companies -- aggressively going after companies that would fit into its matrix when the company knew they were for sale at a good price. For a while, Wohlstetter said, companies such as STSC were too expensive, with their stock selling in the high $20s. But when stock prices declined, Continental moved in and bought STSC for $11 a share.

With the acquisition of STSC and a California computer company, CADO Systems Corp., this month, Continental has "some major part of everything we wanted in our matrix," says Wohlstetter.

As a result, Continental expects to slow its acquisition binge.

However, Wohlstetter adds, "I don't rule out doing something more to strengthen or improve our company if a situation or business arises. We'll improve through buying somebody instead of expanding from within because it's too time-consuming and expensive."

Within five years, Continental hopes the unregulated companies it has acquired will contribute a quarter of its profits -- compared with the 5 percent they contribute today.

The acquisition mania has provoked some concern on Wall Street.

"Continental's diversification has been disappointing," comments analyst Edward M. Greenberg with Sanford C. Bernstein & Co. "It's hard to see any real synergy among their various acquisitions and I still question how they all fit together."

Chief among the analysts' concerns is the poor performance of several of the companies Continental has acquired. Executone, the telephone equipment subsidiary, has lost money for the past few quarters, largely because of a product it began marketing last year that was found to be defective. Recalling these telephones -- while providing customers with temporary replacements -- has proved an expensive proposition for Executone.

In the eyes of several analysts, the recent acquisitions of STSC and CADO are also risky because those companies have not been living up to their strong financial performance of recent years.

But Continental's largest gamble by far is its investment in Spacecom, which is under a $2 billion fixed-price contract with NASA for its satellite tracking system. The first satellite to be used in this system is scheduled to be launched this winter. If that and two subsequent satellites fail to function, the company stands to lose $30 million.

"If you are a widow or an orphan, Continental stock is not for you," said Harry Edelson of First Boston. "They are getting a bit aggressive," buying some particularly risky stocks. "I don't consider it as solid a company as some other large independent telephone companies."

Continental officials dismiss these critics.

"It's just silly to suggest that their judgment is better than the collective judgment in our company," Wohlstetter said, adding, "If you never make a mistake, you aren't doing anything."