About the only thing that's clear about digital audio tape is the sound it produces.

DAT is the latest innovation in home audio, combining the crispness and clarity of compact disks with the convenience of tape cassettes. Like the compact disk player and the videocassette recorder before it, DAT has the potential to change the way Americans are entertained and take a major share of the $30 billion U.S. consumer electronics business.

At least that's the way the makers of DAT machines tell the story. But the record industry has a much different version.

"It's a cloning machine" for copying compact disks, said Patricia Heimers, a spokeswoman for the Recording Industry Association of America, the record-makers' trade association. The RIAA has called DAT "the most significant technological threat that the American music industry has ever faced."

"The purpose of these machines is to make copies, and there're no controls to prevent people from doing that," said Robert Altshuler, a vice president at CBS Inc.'s record division. "You can clone away endlessly. That means that all those copies that are made deprive the composer, the performer, the music-publishing company, the record company -- everybody down the line -- of royalties from those copies."

In a heated battle that recalls the famous Betamax war of a few years ago, when movie and television producers squared off against videocassette recorder manufacturers over the legality of home taping of movies and TV shows, the record industry is claiming that DAT's ability to make virtually perfect copies of whatever it records could all but dry up record sales.

The record companies fear that rampant home taping by owners of DAT machines could exacerbate a problem that the industry says already costs it between $500 million and $1.5 billion a year -- tapes made by consumers that then are given to friends who thus don't have to buy the record. Because of the high quality of DAT, the record industry argues, home tapers will be able to make copies of compact disks that sound as good as the original studio master tape.

But the DAT makers say the claims of a home taping problem are exaggerated, and argue that record companies want to nip DAT in the bud to protect the companies' investments in compact-disk manufacturing and marketing facilities.

It took the Supreme Court to decide Betamax -- in favor of the videocassette recorder makers. This time around, Congress is being asked to determine the future of DAT.

The two sides have squared off in a classic Washington battle, each claiming grass-roots support and complaining about the size and tactics of the opposition, even as both sides employ high-priced lobbyists and lawyers to press their cases. The DAT makers have revived the Home Recording Rights Coalition, consisting of the Electronics Industries Association, large electronics manufacturers and some big consumer groups, to fight the battle just as the HRRC was in the vanguard in the videocassette recorder fight. The record industry has gathered major music publishing and licensing organizations, record companies and musicians' unions into the Coalition to Save American Music.

The battle is raging fiercely on Capitol Hill. Both sides have mustered studies and expert witnesses -- including recording stars Stevie Wonder and Emmylou Harris -- to argue their case before several congressional committees. "I would like to make tapes for my personal use with the DAT machine," Wonder told a Senate subcommittee in written testimony last month. But Harris, speaking for the other side, told a House subcommittee: "Maybe people think they're flattering us by copying our music. But the simple truth is that they're choking off our livelihoods."

Bills introduced in the Senate and House and backed by the Reagan administration and the record industry would require that when DAT recorders go on sale in this country in a few months, they carry a "copycode" chip that would prevent the machines from recording specially encoded compact disks.

The makers of DAT machines vehemently oppose this proposal, claiming that the encoding process distorts sound quality -- a point that Congress has asked the National Bureau of Standards to settle. The DAT makers also are opposed to another suggestion, that a royalty be charged on the sale of DAT tape and machines to cover the record industry's home-taping losses.

Many in Congress are troubled by the idea of regulating DAT technology. It is highly unusual, if not unprecedented, for Congress to pass legislation controlling a technology for other than health or environmental reasons, and many representatives worry that by regulating DAT, they may be bowing to the commercial considerations of the record industry.

There also are concerns about underlying currents of Japan-bashing in the DAT argument. All makers of DAT are Japanese companies -- most of them were involved in the earlier videocassette fracas -- and virtually all of the major record companies are American-owned. "Just as most of the premium blank tape and recording machines now used for the home taping of music originate in Japan, so will DAT tape and machines come from Japan," RIAA President Jason Berman testified before a House subcommittee in May. "It will therefore be these foreign hardware manufacturers who will increase their profits at the expense of the American music industry."

The record industry tried unsuccessfully to tack DAT legislation onto the trade bill this spring before deciding to pursue the issue as a copyright problem -- where many in Congress think it belongs. "It is a very interesting and fascinating intellectual property issue," said Sen. Dennis DeConcini (D-Ariz.), chairman of the Senate Judiciary subcommittee on patents, copyrights and trademarks, one of the key battlefields of the DAT forces.

The debate over DAT is being played out against a ticking clock -- the impending American release of the first DAT machine. Marantz, a Japanese electronics company, has said it will introduce a DAT tape deck -- price tag: $1,500 -- in October, regardless of the status of DAT legislation. Other companies, which have been holding back because of the fight in Congress and technical problems, are expected to follow soon after. Some in the record industry fear that it will be tougher to get legislation against DAT once it hits the market, and they plan to slow its sales by refusing to release pre-recorded tapes for the machines.

No one knows exactly what the market will be for DAT. At least at first, it will be an expensive proposition -- $1,200 to $1,500 for a recorder, another $8 to $14 for each blank tape, although those prices are sure to come down.

Will American consumers, just now making the expensive switch to compact disks, want to adopt still another new sound technology? Nobody is really sure. "I've got some question about whether these things will actually ever have a market," said Rep. Al Swift (D-Wash.), a hi-fi buff who has opposed copycode legislation.

DAT is the latest in a string of Japanese-made consumer-electronics wonders to hit these shores, and in many technical ways, it resembles an amalgamation of the two most recent successes, VCRs and compact disks.

A digital audio cassette is somewhat smaller than a conventional audio cassette, somewhat larger than a microcassette. Its high-quality tape is packaged in a plastic case similar to that of a videocassette tape, with a lid that snaps up to expose the tape to a rapidly spinning recording/playback head. Like the digital compact disk, DAT records sound by converting it into thousands of numbers; in playback, the numbers are converted back into sound, with no tape hiss or loss of quality from the original.

That gives it the crystal clear sound of the CD, with a big plus -- its ability to record. But to the record industry, that's a huge minus.

"The recordings that you make will be CD quality. There will be no degradation of sound," Heimers said. "Your first copy will be as good as your 100th, and your 100th will be as good as your master."

Heimers and others in the record industry believe that would revolutionize home taping. Because DAT makes a nearly exact copy, a home taper would not even need the original CD to make a perfect reproduction -- any DAT copy could serve as the original.

Should that happen, record company officials argue, record sales would plummet. One copy of a CD could produce an endless number of DAT clones, each one wiping out a sale, they say, and the lost profits would keep the industry from signing and developing new artists. "If that goes on unabated, eventually what will happen is there will be no new artists recorded," Altshuler said. "It will eliminate the possibility for artists to find places to have their music recorded and marketed commercially."

Record industry complaints about home-taping -- with accompanying doomsday scenarios -- are nothing new, however. For years, the industry has claimed that conventional taping is costing it hundreds of millions of dollars a year -- as much last year, according to RIAA estimates, as one-third of the industry's total sales of $4.65 billion.

But those numbers have been disputed by the audio equipment makers, and there is little or no independent data to determine which side is right. The record industry, for instance, claims that most home taping is done by teen-agers who turn out taped copies of albums for their friends. The other side says that most home taping is done by individuals who buy a lot of records and record spare copies for their own use in car tape decks, Sony Walkmans and elsewhere.

At the heart of the home-taping dispute is a fundamental copyright question: Does the purchase of a recorded work give the buyer the right to retape it for personal use? In the Betamax case, the Supreme Court ruled that videocassette recorder owners could tape programs off TV for their own use -- but the court did not take up the issue of audio taping. Revisions to copyright law passed in the 1970s also left out home taping.

The record industry thinks home taping is flat-out illegal. "When they begin taking the guts out of it, stealing our property, something must be done," Heimers said. However, the industry's previous attempts to win anti-home-taping legislation -- principally through a royalty on blank tape -- have been unsuccessful.

Record industry officials concede that the quick popularity of conventional cassette recorders and VCRs made it difficult to take action to regulate them retroactively. By attacking DAT before it hits the market, the record industry hopes to win the battle before the new technology becomes entrenched in the marketplace.

"We're just trying to stop technology from killing us. We're not trying to stop technology," said Hilary Rosen, vice president of the RIAA for government affairs. "The copyright laws that have developed in this country to protect creative output must keep up with technology. ... DAT is the first wave of this new technology. Now is the time to deal with it."

Faced with political opposition to the idea of a royalty, the record companies turned to the copycode concept as a technological solution. If a user attempts to use a copycode-equipped DAT machine to tape an encoded compact disk, the sound comes and goes in 25-second intervals. The protection apparently does not affect recording from conventional records, tapes and radio broadcasts, or even of compact disks currently on the market, which are not encoded. Some in the record industry also have suggested that non-encoded CDs be made available, at a higher price, allowing DAT owners to tape at a premium.

CBS, which developed copycode, has offered to license the technology for free to other record companies, and to sell them encoding machines at cost.

But the copycode idea -- contained in bills introduced in the Senate by Sen. Albert Gore Jr. (D-Tenn.) and in the House by Rep. Henry Waxman (D-Calif.) -- has fired a separate controversy over the effect the coding has on recorded sound. Copycode works by blanking out a small "notch" of sound at the high end of the audio frequency -- so high, dogs can't even hear it, proponents say. But DAT makers claim that their tests show that the notch is audible and distorts the sound of the compact disk. "I take great pride in trying to provide quality music to the public, and I am distressed to learn that the integrity of my music will be compromised by the encoding process," Stevie Wonder testified recently.

That argument brings a retort from record industry officials: Since the CBS system is proprietary, there is no way the equipment manufacturers could have done an accurate test.

Such wrangling caused congressional leaders to throw up their hands and ask the National Bureau of Standards to act as an impartial artbiter of copycode quality. Even that caused problems -- the bureau says it does not have the $150,000 to $200,000 needed to test the efficacy of the copycode system, and it appears that to pay for it, Congress will have to make a special appropriation, move money from elsewhere in the Commerce Department budget, or get the record industry and the DAT manufacturers to contribute funds for the test.

That dispute is expected to be settled in a few weeks, and the tests are expected to take from two to five months more. By then the Marantz DAT recorders and perhaps others may be on the market.

Should the Bureau of Standards agree that copycode works as advertised, sources on both sides of the issue expect a close vote in Congress on the proposal to require its installation in DAT machines. DeConcini, for instance, says he is not yet convinced that DAT poses a serious threat to the record industry. "To me, it has a lot to do with economics, and that was not demonstrated overwhelmingly in the first set of hearings," he said.

And Rep. Robert Kastenmeier (D-Wis.), chairman of the House subcommittee on courts, civil liberties and the administration of justice, another subcommittee considering DAT legislation, says he is concerned about the precedent that anti-DAT legislation could set. "It's a very, very poor precedent for this country to be keeping out the newest forms of technology," he said.

Kastenmeier, who oversaw hearings on the videocassette controversy a decade ago, also worries about attacking DAT without limiting other forms of home taping. "It would seem inconsistent to single out digital taping, particularly on the grounds that it's more perfect as a process," he said. "I think that leaves us in a very untenable position, either on copyright principles or on trade or economic principles."

Should copycode legislation falter, or if the Bureau of Standards decides that copycode has a deleterious effect on sound quality, many observers expect the record industry to adopt a fallback position of requesting royalty payments on DAT tape or machine sales, which may be more politically acceptable.

As it is, the proposed legislation contains room for compromise. The copycode requirement would only last for three years, which record industry officials hope would provide some inducement for the DAT manufacturers to bargain for a mutually agreeable permanent solution. Indeed, both sides agree that their dependence on one another demands some sort of eventual compromise.

"One industry is not good without the other," the RIAA's Heimers said. And Allan Schlosser, vice president for consumer electronics at the Electronics Industries Association, said, "This is not a holy war. There is life after DAT. These two industries need each other. ... they've grown together.

"But obviously," he added, "we're going to have to defend our interests."