Washington wonders how to patrol your new electronic playground

It used to be so simple. Your TV set received three main stations - NBC, ABC, CBS - and a handful of UHF channels that specialized in reruns of ''Hogan's Heroes'' and pro wrestling. Phones were rented, and all long-distance calls went via AT&T.

Today, the apartment of Tim Giles (not his real name), a young government official, is more typical. In the bedroom, underneath a giant Sony color TV, sits a videotape recorder, its blue lights blinking inscrutably. A coaxial cable emerges from the wall nearby, carrying 36 cable-TV channels. The phone on the Danish-modern desk isn't hooked up to a discount long-distance phone company - but only because ''I have a WATS line at work,'' says Mr. Giles.

Cable TV, videotapes, the MCI phone company, and their brethren have shattered the once-stable world of telecommunications. But while more and more US homes turn into electronic playgrounds, Washington is still struggling to decide how, or if, it should control new telecommunications technologies.

And the federal government's decisions on cable and commercial TV deregulation, videotape licensing, the AT&T breakup, and other issues will greatly affect the price and quality of these electronic services.

Take The Great Videotape War: On one side of this fight is the motion-picture industry and its allies, who feel they should get a slice of the exploding videotape market. On the other side are manufacturers and retailers of video equipment, who charge that Hollywood is trying to muscle in on somebody else's business.

At issue is whether Hollywood should receive a licensing fee for every videotape and videotape recorder sold and rented in the United States. Bills that would levy such fees are now pending in Congress. Legislative action, however, will probably wait until the Supreme Court rules on whether home taping , in essence, steals from the movie industry by violating copyrights.

It isn't yet clear how much the proposed license fee might cost. For Tim, who reuses videotapes and buys new ones only occasionally, the fee would probably add little more than an extra dollar or so to the cost of renting a movie for the weekend ''video parties'' he holds occasionally.

Five years ago, of course, Tim probably wouldn't have considered holding such a gathering, since his guests would have been forced to watch predictable network fare. But the rise of videotapes and cable TV has made video parties popular, and led to another hot issue now being considered in Washington - deregulation of commercial television.

Currently, the FCC keeps close watch on the programming mix of the 844 commercial TV stations in the US, making sure they carry no more than 16 minutes of commercials per hour, and that 10 percent of their programming consists of nonentertainment shows.

But Mark Fowler, chairman of the FCC, says that this oversight is no longer necessary to protect the public interest, since the US public now has such a rich array of video choices. So the FCC has proposed eliminating commercial limits, as well as requirements that stations carry public-interest shows and keep program logs.

''Stations would continue to be held responsible for the 'needs of the community,' but rules would be much less formal,'' says Robert Ratcliffe, chief legal officer of the FCC's mass-media division.

The House of Representatives, however, is taking a different tack. A broadcast bill now in subcommittee would set stricter requirements for public-interest shows. In return, TV stations would find it much easier to renew their FCC licenses.

''The FCC is just trying to make a political statement,'' argues a House staffer who works on the bill, adding that TV markets aren't as diverse as FCC chairman Fowler believes.

The debate over broadcast deregulation hinges on whether cable TV is now a powerful enough medium to truly compete with commercial stations. Without such competition, say some critics, unregulated commercial stations might simply run long strings of ads.

''I think it's premature to deregulate TV,'' says Charles Ferris, former FCC commissioner.

And the control of cable itself is yet another issue now being considered in Congress.

A cable deregulation bill has already passed the Senate. The legislation would limit the power cities now have over cable systems within their borders.

In the long run, the bill would probably cost Tim Giles money, since it would end community control of cable rates in most areas. But backers hope it will hasten the spread of cable to areas that aren't wired yet.

Of course, changes in telecommunications regulation are going to affect the phone on Tim's desk, as well as the picture that comes over his giant Sony. When AT&T breaks up next January, his bill for local phone calls may go up - as such calls were subsidized from 35 to 50 percent by long-distance revenues.

But some members of Congress are trying to keep that from happening. Sen. Bob Packwood (R) of Oregon, chairman of the Commerce Committee, is scheduled to introduce a bill this Thursday that would require long-distance companies, such as AT&T and MCI, to pay subsidies to keep the cost of local service low.