AN AMERICAN FAMILY returns late on Sunday night from a summer vacation. Although the family has been gone for a week, the lights in their home have just been turned on automatically, and the air conditioner has begun to cool the rooms to a comfortable 75 degrees.

As they unpack, one family member checks the "electronic mailbox" for important messages, while another orders dinner from one of the several local restaurants whose menus appear on the television screen.

The auto repair shop has been closed all weekend, but Dad makes an appointment to have the car serviced the next morning. Although the local newspaper hasn't been delivered, the family skims the headlines and reads entire stories by spending a few more minutes in front of the tube. Even that day's baseball scores flash on the screen at the press of a button.

Is this a science fiction writer's vision of family life in the year 2001?

Not any more.

It is becoming reality in Coral Gables, Fla., where 200 families are starting to use Viewdata, a new technology which could transform today's home into tomorrow's electronic information center.

Viewdata and its sister technology, Teletext, link telephones and televisions with computers to deiver words, numbers -- even graphics -- electronically.

Experts predict that it may take engineers a decade to perfect these systems. But to get out of the lab and into the home, Viewdata and Teletext will have to survive a long, and perhaps perilous, trip through boardrooms, courtrooms and the halls of Congress.

Bitter disputes already are brewing as newspapers, cable television systems, telephone companies, broadcasters and equipment manufctuers start competing for the new market. Industry analysts haven't picked a winner yet, but most agree there is more at stake than market share. Second-rate service, high consumer costs, long regulatory delays and a challenge to the First Amendment itself could come as part of the industry struggle.

From the consumer's perspective, both Viewdata and Teletext are relatively simple systems to operate. Viewdata uses old-fashioned wire -- telephone lines or cable television facilities -- to transmit information. Given the modern computer's almost unlimited capacity for what the purists call "data," huge quantities of information can be stored, plucked out by the consumer and sent to a modified television screen.

Transmission by wire may sound outmoded, but it has one major advantage: it makes Viewdata a two-way system -- just like the telephone. As a result, consumers can interact with the computer, which store,s processes and send the information. A sports fan overwhelmed by a screen full of scores can erase them all in a second to find just one.

Teletext broadcasts information by using an inteval in the television signal when no picture is being transmitted. British systems broadcast roughly 100 pages of text every 24 seconds. The pages flip by, one after the other, then the cycle begins again. With special controls, a view can select a page to appear on the television screen.

Teletext is not interactive, but its ability to transmit information is enormous. With full-channel capacity, viewers would have access to 3,000 pages of information every 24 seconds, more than a million pages of text once every three hours.

Consumers may not need or want this much information but engineers soon will be able to deliver systems that can accommodate a wider range of viewpoints than any other communications medium in history.

This opportunity for freecom and diversity is by no means guaranteed, however. Competing corporate interests could push the Congress, the regulatory commission and the courts to adopt policies that lead to the development of systems that are relatively limited, inexpensive to produce and which pose no threat to established media.

An example of this trend may have already occurred in the Public Broadcasting Service's closed captioning of TV programs for the hearing-impaired.

Closed captioning is a Teletext-like service in which subtitles are added to television programs and displayed to viewers with special "decoders," which Sears sells for about $250.

Such specialized decoders for the deaf already are unnecessary on the more advanced French and British versions of the same system. More important, the PBS closed-captioning service "wastes" the television signal, reducing by 20 to 30 percent the information capacity which could be available on Teletext in the near future.

Why did PBS select an outmoded, inefficient system? One can only speculate, but it is worth noting that both NBC and Abc warmly supported the PBS choice, CBS opposed the system at the Federal Communications Commission and in other public forums.

Were the other networks afraid to encourage the growth of a new medium that could compete with them for advertising dollars? We can only guess, but in the meantime, the deaf community will be paying higher prices for less service than it should have to. And the government, which funded the closed-captioning project, lost a valuable opportunity to encourage development of a full Teletext system.

Other countries have been more efficient and adventuresome. Britain and France have been especially enterprising in their efforts to use Teletext and Viewdata to increase revenue of the government-operated telephone systems.

The British government, for example, has financed and cordinated the dvelopment of a Viewdata system called Prestel, which offers consumers more than 150 services ranging from electronic shopping to data retrieval. The british Broadcasting Corporation has jumped into the act with a new Teletext service.

The French have combined Viewdata and Teletex with facsimile machines, allowing consumers to send and receive printed messages. Financed by the French Postal and Telecommunications Ministry, this experiment in "electronic mail" should generate more revenues for the government-run telephone system while eventually eliminating the costs of printing telephone directories.

The Canadian government has committed $9 million to Telidon, a more sophisticated version of its British counterpart, Prestel. The Viewdata system is already being used by cable television systems and telephone companies throughout Canada.

Telidon may soon cross the border into Portland, Ore., where a Canadian firm is promoting the system to win the cable television franchise.

What else is happening here at home? Using its stations in St. Louis and other cities, CBS is conducting one of the most ambitious Teletext experiments today. But the CBS project is just a technical experiment; no one is actually using the service.

Technical questions aside, CBS' or any other broadcasters' activity in developing Teletext systems raises a series of perplexing policy questions. Should broadcasters, who are licensed to broadcast television programs, be allowed to extend their government-conferred monopoly to data transmission? Or should new licenses be issued for Teletext services? Which if any, of the current broadcast rules should apply to Teletext? The requirement to cover controversial issues? The obligation to present opposing viewpoints? The prohibitions against obscenity or indecency?

The jury is still out, but in the meantime the newspaper industry has launched its own experiments with the new technology. The most promising of these new ventures is under way in Coral Gables, where the Knight-Ridder newspaper chain has begun testing a new Viewdata service. Cosponsored by AT&T, Viewtron uses telephone facilities to supply "more than 10,000 pages of information and shopping services" from Consumers Union, The New York Times, the Associated Press, Congressional Quarterly and others, according to the promotional brochure.

Knight-Ridder's interest in Viewdata is easily explained. Newspapers are natural "information banks." When the day of electronic publishing finally dawns, the newspaper industry wants a place in the sun. Just this year, for example, The New York Times paid millions of dollars for several cable television systems -- system which could prove to be handy laboratories for testing new market applications of the paper's current information services.

The Wall Street Journal, composed in New York, transmits its stories by satellite to plants across the country, where regional editions are put together and printed. With cheap satellite receivers promised soon, what is to prevent the Journal from transmitting information directly to readers' offices and homes, bypassing the printing plant altogether?

Like broadcasters, newspapers face substantial problems as electronic publishers. For example, does an electronically delivered newspaper forfeit its First Amendment protections? The question is not as trivial as it sounds, for newspaper reporters' counterparts -- broadcast journalists -- have never enjoyed full First Amendment rights.

Two landmark decisions from the Supreme Court underscore the distinction -- and dilemma.

In 1972, Pat Tornillo ran for the Florida House of Representatives from Dade County. The Miami Herald came out against him. Tornillo unearthed an obscure Florida statute which provided a right to reply to such newspaper attacks. He demanded space from the Herald. The newspaper refused, but the Florida courts upheld Tornillo's claim. The Supreme Court found the Florida statute unconstitutional.

While newspaper publishers hailed the decision as an important victory for journalistic freedom, broadcasters could only sit back and rue its irony. Just five years earlier, the Supreme Court had upheld an FCC ruling which required broadcasters to give free air time to a person who had been criticized in a syndicated religious program.

Did the Supreme Court contradict itself? Observers who try to reconcile the two decisions are confronted with a single fact: Broadcasters, unlike newspapers, are licensed by the federal government.

The current scheme of licensing began in 1927, when the government tried to impose some order on the chacs caused by an "open entry" policy which allowed anyone to start a new radio station, even if it interfered with an existing one. When the government began to allocate broadcast frequencies and issue licenses to use those frequencies, it created a scarcity in the broadcast spectrum.

Justice Byron White invoked the "scarcity principle" to support his argument that, "When there are substantially more individuals who want to broadcast than there are frequencies to allocate, it is idle to posit an unabridgeable First Amendment right to broadcast comparable to the right of every individual to speak, write or publish."

But what happens when traditional publishers, such as newspapers, use scarce broadcast frequencies? Is a newspaper delivered by Teletext vulnerable to new government intrusion into editorial content? How will First Amendment rights be applied to these new electronic publishers.

No one knows. But one thing is certain: the potential First Amendment problems will depend on the way Teletext systems are designed and regulated. Those systems could have the capacity to deliver more text than anyone could ever read or write. But those same systems could be designed like the one used by PBS -- so limited and restrictive, they virtually ensure that Teletext will be regulated like broadcasting has been.

The legal and regulatory problems posed by the use of Viewdata technology are different, but no less profound. If AT&T develops a system like Viewtron in conjunction with a newspaper, will that system be regulated like the telephone industry? If so, Knight-Ridder could be forced to make its service available to anyone on request or to allow other competing newspapers to include their stories in the package.

As long as the programs are experimental, these problems may seem remote and speculative. Their solution, however, could determine how quickly Teletext and Viewdata appear in American living rooms.

The participation of AT&T and other telephone companies raises a host of difficult questions. In addition to cosponsoring the Viewtron experiment in Coral Gables, Ma Bell has also tested an "electronic information service" in Albany, N.Y. The system provides up-to-date listing of local telephone numbers and some Yellow Pages -- like advertising to a limited number of customers.

AT&T's projects may be no more than experiments, but the Carter administration has proposed to Congress that the corporation be prohibited from offering any information service "designed to inform the electorate of issues of public concern." Another administration "white paper" cautioned against allowing Bell to provide "electronic mass media" services, such as broadcasting, cable television, video newspapers of magazines.

The Congress is now considering communications reform legislation which incorporates the White House bar on mass media services, while allowing Bell to offer the transmission facilities for such services. The bill would allow AT&T to provide facilities needed for Viewtron or to offer a full-fledged service of electronic "telephone number or address listings" and "directory assistance."

Newspaper publishers can spot a competitor when they see one. Electronic yellow pages could erode newspapers' local listing revenues. Thus, despite the proposed legislative safeguards, Ma Bell's electronic yellow pages could create a storm of controversy if and when AT&T attempts to expand its Albany trial.

General Telephone and Electronics (GTE), the Avis of the telephone industry, already has acquired the U.S. license for Britain's Prestel. GTE also is launching Telemail, a service that will allow subscribers to send electronic messages which could be stored in a computer and retrieved at the customer's convenience.

Cable television isn't about to be outdone by its potential competitors in the telephone, broadcast and newspaper business. Some cable operators already are looking beyond their traditional role as "giant TV antennas" transmitting only movies and sports.

Cable is a hybrid -- often regulated like a TV broadcaster but containing features of a local monopoly, like the telephone industry. As a result, cable's entry into information services could produce a mixed bag of regulatory problems. Like broadcasters, cable operators must present all sides of controversial issues and all political points of view when they originate programs.

These requirements discourage cable operators from developing electronic newspapers, or at least encourage their industry to rely on someone else to "program" their channels. But if a city's only cable opertor turns to one local newspaper to supply a news service channel, shouldn't all the other papers in town have equal access to the same facilities? That is, after all, the way another local monopoly -- the telephone company -- must operate.

The history of cable TV may hold another lesson. In the 1960s, the FCC was beset by intense political pressure from the broadcasting industry and totally unable to come to grips with the implications of cable technology. The commission responded with a six-year freeze on the new industry followed by a series of regulations which virtually strangled cable television in its infancy.

Many observors fear that history could repeat itself unless Viewdata and Teletext system come to grips with some of the legal and regulatory problems posed by these systems in the early stages.

The battle over the home information market is just beginning. It's taking placed on a murky, undefined battlefield.

Many argue that the U.S. consumer already is so flooded with information, and that new services will continue to be secondary to newspapers, books, magazines, broadcast stations and the telephone. Others claim that Viewdata and Teletex will help the consumer to manage this information glut.

Still others see the battle as an Armageddon -- a revolutionary transformation of American society for which no one is prepared.

Information systems may become monopolistic or competitive. Professional editors of federal regulators could control the editorial process. No one has made the choice. Still more discouraging is the fact that few people are even talking about the issues.