Couch potatoes may soon be able to order a pizza, check their bank balances or take a college course merely by aiming an electronic gun at their television sets, thanks to a new technology that got the federal government's preliminary blessing yesterday.

So-called interactive TV -- named because it enables viewers to do more than just stare passively at their screens -- could become widely and cheaply available starting in about a year if the Federal Communications Commission adopts a plan that would clear the way for one form of the technology.

The commission yesterday proposed setting aside a portion of the radio spectrum so that, on two broadcast channels in each metropolitan area, viewers equipped with special equipment could "communicate" with their television sets. On these channels, a viewer would receive a still-picture image on his screen and then instantly be able to do a variety of tasks, from balancing a checkbook to ordering carry-out food.

The system envisioned by the FCC wouldn't allow TV audiences to select endings for TV shows or choose camera angles on a football telecast, as a handful of experimental interactive channels now offered on cable TV systems around the country are capable of doing. But the proposed radio-based system would provide both broadcast and cable viewers an expanded range of services, such as on-screen TV guides, shop-at-home catalogues, access to automatic-teller accounts and the latest news from a wire service without requiring special cables or use of a telephone or personal computer.

"Potentially, every home in the country is a subscriber to this system," said Ralph Haller, chief of the FCC's private radio bureau. "As we get into an age where people are accustomed to more immediate interaction {with the electronic media} there will be more and more demand for this integration of video and digital services."

If the FCC adopts its proposal, it would give an important boost to TV Answer Inc. in Reston. Both the FCC and the company said it is the only firm to have developed a system capable of utilizing the radio spectrum for interactive broadcasts. TV Answer, whose board members include former FCC chairman Mark Fowler, originally proposed using the radio spectrum for the system.

The TV Answer system consists of a black box the size of a standard videocassette recorder and a hand-held remote control device that looks like a futuristic pistol. The box, which sits on top of a TV set, is a radio transmitter-receiver that also contains a computer processor that converts radio impulses to video text. Viewers can make selections from a variety of still-picture "menus" that appear on the TV screen by pointing their infrared remote control gun at the service they want. The responses are then transmitted back to the source along a network of small radio towers, much like a cellular telephone network.

By punching in a response to a question displayed on a screen, for example, local audiences would be able to vote in a TV poll. The system may also someday permit consumers to review airline schedules and order tickets or order a pay-per-view movie. It can even be utilized to program a VCR, a task that still confounds millions of people.

In yesterday's demonstration, a viewer was able to interrupt a telecast of Music Television with a menu screen that asked, "Would you like to buy the record you just heard?"

Fowler and Fernando Morales, TV Answer's founder, declined to say yesterday how much the equipment would cost viewers. But they said some of the costs could be borne by marketers that sign up to use the system. Assuming the proposal gets final government approval, Morales said the TV Answer system could be in about 80 percent of all U.S. homes by 1997.

TV Answer conducted a yearlong test of its interactive system in Fairfax County's cable system last year, using about 500 homes. It offered two interactive programs: "Impulse News," which allowed viewers to register their opinions about the day's news events; and "Interactive Jukebox," an hour-long show featuring viewer-selected music videos and trivia games.

The proposed system faces potential opposition from the National Association of Broadcasters, which is concerned that the radio transmissions will interfere with TV broadcasts on Channel 13, a spokeswoman said.

TV Answer is a privately held company that has received about $20 million in backing from a group of Mexican industrialists. It was founded by Morales, an electronics engineer who was a consultant to Mexico's national TV system.

Rich Miller, the firm's vice president of marketing and programming, estimated that it will cost about $100 million to set up transmitter cells around the country for a nationwide interactive network. However, the FCC has proposed granting licenses on a local basis, with two licensees in each market.