The time is 1986. The place: a wealthy Washington suburb that has just installed a top-of-the-line cable television system.

Within a matter of months, some strange events begin to unfold in the homes of many subscribers:

Regular viewers of public television programs suddenly find their mail boxes flooded with fund-raising appeals from various charities.

In the middle of the night, television screens light up and a booming voice warns of an impending tornado.

County officials pick a new subway route, but only after residents "vote" on the route through their television sets.

A candidate for county office wins his race after releasing an itemized list of the X-rated movies his opponent has watched on TV.

That, say some of the nation's communications experts, is a glimpse of the promise -- and the problems -- that the fast-growing cable TV industry soon will bring to many communities, including those in the Washington area. While much of the public's clamor for cable TV has focused on the lure of first-run movies and shop-at-home programs, others are troubled by what they say are the unprecedented questions of privacy that the new two-way cable TV systems also pose.

"Sure it's scary," says Chris Weaver, vice president of science and technology for the National Cable Television Association, the cable industry's trade group. "[Cable television] raises all kinds of issues of privacy and control of information. . .

"It's not being dealt with on an industry-wide basis because it hasn't demonstrated itself as a burning fire yet. But it will."

Weaver and others in the industry readily acknowledge the new technology of cable TV can be used to collect a mind-boggling array of information on each of a system's subscribers, unfettered by laws, regulations or even industrial guidelines that would regulate the electronic snooping.

Since regulation of cable TV is, for the most part, a local issue the question of cable privacy rests squarely in the laps of Fairfax County Board Chairman John F. Herrity and Prince George's County executive lawrence Hogan -- local politicians who have been thrust into the role of mini-communications czars. And that makes many local politicians queasy.

"I just get the feeling that here we are -- We don't know what we're doing, but we're plunging on blindly anyway," says Fairfax Supervisor Martha V. Pennino, who recently succeeded in winning an extension of several months for the county's planned examination of cable television. "My greatest concern is that we don't know enough about the [cable television] impact on lifestyle as we know it."

It is recent technological advances enabling consumers to "talk back" -- send messages -- through their television to the cable system that are triggering new controversy in many communities. This equipment, which lets viewers use their television sets for banking, shopping, public opinion polling, paying bills, burglar alarms and a host of other uses, is certain to be included in the cable systems being planned in Washington area, cable spokesmen say.

Communications experts are predicting that services like these will lure an estimated 50 percent of American homes into the cable fold by the beginning of the next decade, compared with the 20 percent of American TV viewers who now subscribe.

The Washington area, one of the most financially alluring cable markets in the country, is likely to see the advent of two-way cable within the next five years, experts say. Cable companies already operate one-way systems in Rockville, Reston, Arlington, Woodbridge, Alexandria, and a few other communities. All of them have the capability of being converted to two-way systems.

"Theoretically, somebody could gather a dossier on your viewing habits and other things, and that information in their hands could lead to a lot of harassment," says John R. Harter, counsel to a New York state commission on cable television. "My own personal feeling is that it should be covered by federal law -- that would make it a lot easier.But the trouble is, they [the legislators] just can't keep up with technological advances."

"This is one of those totally uncharted areas," says Professor Thomas Emerson, a Yale Law School privacy expert. "The only laws we have now involve government officials coming into your house, or placing a tap on your phone or bugging you or something.

"But this doesn't involve the government. It's really a private cable company we're talking about. There's nothing in the Constitution that covers that, and nothing in the statutes."

Leaders in the area of a two-way cable are vocal in their assurances of consumer privacy. They say the whole subject is a red herring because there have to date been no invasion-of-privacy complaints from cable viewers.

Warner-annex Cable Communications Inc., which runs the pioneering two-way QUBE system in Columbus, Ohio, has a corporate policy prohibiting the collection of specific data on any individual subscribers. Warner's pledge may be enough for its viewers, but critics say they worry about other, less scrupulous cable operators who would opt for the highest return on their system by selling off cable consumer data to the highest bidder. And, critics note, there is no question that many people, particularly advertisers, would like as much data as possible on cable viewers.

Before its defeat, the Carter administration was urging the cable industry to adopt voluntary privacy guidelines. Such guidelines, under the White House plan, would assure that customers be told what information will be collected and how it will be used, that they have a right to see and correct information being held about them, and that government access to such data be restricted.

But with Carter headed out of office and the industry attitude toward such regulation pronounced, it seems likely that the White House plan is dead.

"Maybe we should examine it but even that is possibly premature when the industry has so much to do," says Gustave Hauser, Warner-Amex's president. "We should just be left alone for a while to creatively find our way to providing what people want."

Meanwhile, the technology for two-way communications is advancing at a rate that troubles civil libertarians. Texas-based Tocom, Inc., which is battling Warner-Amex for control of the two-way equipment market, says it has perfected an "Emergency Alert" system that will be able to turn on all of a cable system's television sets in case of emergency, set them at a pre-selected channel and turn up the volume. The system, expected to be installed in Omaha this spring, is intended for use in weather and civil defense disasters. o

Syracuse, N.Y., residents are testing out a fire and police alert service with their cable system. The city also is considering enlarging the system's data bank to include specific information about each home's construction and inhabitants.

In Coral Gables, Fla., American Telephone & Telegraph and the Knight-Ridder newspaper chain are cosponsoring an experiment that offers home shopping and banking services through a marriage of television, telephone and computer technologies. Called View-data, the system gives home shoppers the choice of ordering goods from Sears Roebuck; J.C. Penny Company, Inc.; Grand Union Supermarkets, Eastern Airlines and a host of other local merchants. Sponsors of the experiment say it could be applied to cable television systems as well as to telephone lines.

The Viewdata system also will provide the subscriber with shopping information, news, airline schedules, local restaurant listing and prices, energy-saving tips, sports information, and entertainment reviews. Similar tests, involving The Dallas Morning News, The Los Angeles Times, The Washington Post, The Chicago Sun-Times and other newspapers, are in process in selected markets around the country.

Local officials hold what presently is seen as the most effective tool in regulating cable television: the franchise agreements through which a cable company may gain exclusive wiring rights to their communities. Because of the question, more communities are writing restrictions into their agreements.

Fairfax County, for example, will require cable companies to get the written consent of a subscriber before they monitor or reproduce any signal from an individual home. The county's cable law does not, however, place any limits on the use or possible sale of such information.

The Prince George's County ordinance is similar, but the county council there is considering strengthening it at the request of a citizens commission. The group's proposal would prohibit a cable operator from distributing any cable-gathered information in a way that could be traced to an individual viewer. It also would prohibit the cable operator from requiring that a prospective subscriber waive his privacy rights as a condition for joining the system.

In Prince William County, supervisors took just the opposite approach. They voted not to regulate cable at all, deciding instead that the public's interest would be better served by unrestricted competition. "I don't understand all those big laws," said Prince William Supervisor James McCoart at the time. "All I know is that I don't want my people to have to pay extra."