Although few of us were aware of it, television viewers in the Utah area part of an experiment in telemarketing.

Will we be willing to buy "Twin Peaks" T-shirts by calling a 1-800 number?It's a little more complicated than that, but all those T-shirt commercials you've been seeing on KTVX Ch. 4 (did you notice they were only on Ch. 4?) are part of a test by ABC. It's the first time the network has become directly involved in marketing merchandise from one of its shows through telephone sales.

By now, the spots are becoming very familiar to anyone who watches KTVX. The one-armed man (Al Strobel) enters the Twin Peaks sheriff's station carrying his traveling salesman case. But as Lucy (Kimmy Robertson) soon discovers, he's not selling shoes - he's selling Twin Peaks Sheriff's Department T-shirts!

Then we're told about the price and the 1-800 number we have to call.

Believe it or not, David Lynch himself directed the commercial.

"ABC had been exploring something like this for quite some time," said Jeff DeRome, the network's manager of media relations. "We'd been getting a lot of calls asking where `Twin Peaks' memorabilia is available."

But ABC is still just testing the waters on this telemarketing venture - Salt Lake City is one of only 10 markets where the spot is running during January.

"They're all medium-size markets. They're geographically diverse, and they're all where `Twin Peaks' has done well among 18- to 49-year-olds," DeRome said.

The other nine cities are: Albany, N.Y.; Columbus, Ohio; Durham, N.C.; Fresno, Calif.; Kansas City, Mo.; Little Rock, Ark; Nashville, Tenn.; Portland, Ore.; and Seattle.

One of the big differences between this telemarketing scheme and all the others is that the network and the local station each receive a commission

It's up to the local station what times and how often the spot runs.

Even if this campaign is successful - and there's no word on that yet - ABC officials don't expect that we'll be seeing a lot of similar efforts.

"I don't think that this will open the floodgates to telemarketing because it has to be a special show," said DeRome. "It has to be a show that fans really want memorabilia of.

"I don't know if your average `Jake and the Fatman' fan wants `Jake and the Fatman' memorabilia."

"Twin Peaks" fans, on the other hand, have already shown a surprising interest in items related to the show. "The Diary of Laura Palmer" shocked almost everyone when it appeared on the best-seller lists. And sales of the "Twin Peaks" soundtrack have exceeded everyone's expectations.

Not that these T-shirts are exactly cheap - would you believe $13.95 plus $3.25 shipping and handling. So you'd think only real "Twin Peaks" fans would be interested.LEO'S IDENTITY: The name of the actor playing vicious, until recently comatose Leo Johnson on "Twin Peaks" probably isn't particularly familiar to you - Eric Da Re.

However, if you drop the "Da" and Anglicize the "Re" to "Ray," it could start to look a bit more familiar.

Particularly if you discover that that's exactly what a Hollywood studio did back in the '50s, changing Eric's father's name to Aldo Ray.

Not that Eric had exactly intended to follow in his father's footsteps. Like so many of David Lynch's casting decisions, this one came from nowhere.

"Emmy" magazine reports that Da Re was working as a casting director on "Peaks" when he caught Lynch's eye.

"I was on my way out the door," Da Re told "Emmy" in its February, 1991 issue. "A few people from the office came running after me, telling me to come back because David had nobody to read a part. So I reluctantly went back in, because I felt a little bit embarrassed.

"I read with a few people, and word went around that David thought I was really good, which I thought was a joke."

Within a week, the mild-mannered casting director had been cast himself as sadistic, murderous, drug-dealing Leo - a character Da Re doesn't think is all that bad, really.

"The fact of the matter is, his wife is cheating on him," he said. "He's not that bad. He's trapped more than anything else. He's gotten involved in dealing drugs and can't get out. That could be where his anger is coming from."

Yeah . . . but Leo seems to enjoy being a monster.