Rriinngg! "Hello, we're a survey on what type toothpaste your family uses . . . "

Rriinngg! "Hello, I'm from Junk Publications and for $14.95 a year your family can enjoy 12 budget issues of . . . "

Rriinng! " . . . pant, pant . . . I'd like to &()$& you and . . . "

Ring! I'm sorry but that party has an unlisted number."

Unlisted. The magic word that brings succor to jangled ear drums, relative quiet to parents of teen-agers and headaches to bill collectors.

For years the rich, the famous and the sought-after have known the privacy that having an unlisted phone number brings. Now the habit is spreading to the masses.

In Washington, where contact is everything, more and more people are retreating behind unlisted numbers. Twenty-eight per cent of all metropolitan owners have restricted numbers of one type or another. And the numbers are growing, with restricted number requests up 2 to 3 per cent in the last five years.

The phenomenon is apparent in other large urban areas as well. In Los Angeles, a mecca of privacy aficianados, 38 per cent of phone owners have restricted numbers. In Chicago the number of unlisted phone numbers has jumped from 20 per cent in 1970 to 33 per cent today. In New York, the percentage is up a third from 1971.

"There are no special kinds of people who want their numbers restricted," says Webb Chamberlain, new service supervisor for the C&P Telephone Co. "And you don't have to justify why you want to have your number restricted."

The telephone company does, however, point out the value of having a number published in the directory, especially for emergency situations.

"The operator won't give out non-published members even in an emergency," Webb says. "The only thing that an operator can do is call the party and give them the information or the number of the inquiring party so they can call back."

In addition, Chamberlain says, the customer search for privacy in the unlisted ranks cuts down the usefulness of the telephone network.

"To some extend, the system isn't as useful to a subscriber if he can't contact the people he wants. And this makes the telephone business a bit more difficult. But it's the prerogative of the customer whether to list a number or not and the only restraint is the additional fee."

Yes, anonymity costs. For nonpublished numbers, which means the number is unavailable from any source, there is an additional 40 cents tacked on the monthly bill; for unlisted, which means the number is not in the directory but is available through Directory Assistance, the fee is 20 cents extra.

The reasons why people want restricted numbers are numerious, but fear tops the list, accroding to Juan Cortes, a professor of criminology and psychology at Georgetown University.

"Many people now receive obscene phone calls, and their first reaction is not just to change the number but to make it unavailable altogether," Cortes says.

Families with teen-agers frequently end up with the parents answering phone calls for their children. "I've seen parents who were slaves to the phone and all the calls were for their teen-age sons or daughters," Cortes says, pointing out that an unlisted number for the adults and a listed number for the younger people is the usual salvation.

For others, Cortes says, the unlisted number is a fight for privacy in a world where it is rapidly diminishing. And there is always the status that many people feel is attached to having an unlisted number.

"People have asked me if we're unlisted for that (status) as well as whether we have some kind of problem or whether we've withdrawn," says Sallie Ann Robbins, the wife of Sabin Robbins IV, who works for Friends of the National Zoo. "But the reason for it originally was some heavy breathing phone calls in the middle of the night right after I'd had a baby. First we changed the number, but when it continued, we got an unlisted number. it's divine."

The Robbinses went a step further in their quest for seclusion. They got a telephone answering machine and had the telephone company fix their phones so they don't ring at all because, Mrs. Robbins says, she is compulsive about answering a ringing phone.

"Some people think waht we've done is terribly cold, terribly efficient, but it's wonderful for business," says Mrs. Robbins, who frequently works out of her home as assistant to a local builder, Curt Hansen. "The children, though, have completely defeated the system. They yell into the machine, telling me to pick up the phone."

For others who want to keep a listed number, the advent of various telephone answering devices that plug into a telephone jack has allowed them to screen out certain calls.

"We were selling maybe two or three (machines) a week five years ago," says a saleswoman at Code-a-phone, one of several companies in the Washington metropolitan area that supply automatic answering equipment. "Today, we sell 125 to 150 a week. Sales representatives want them to get calls when they're out, private individuals just want to screen calls."

For some of Washington's social and political elite, the question isn't whether to list or not list, but where to be listed. Senators, congressmen and the city's social movers and shakers may eschew the telephone directory, which is free and democratic, for the Green Book, "The Social List of Washington." The Green Book must be purchased and is distributed to a relatively select few.

Unlisted numbers and intercepting devices all add up to a case of the pains for bill collectors who are trying to track down deliquent accounts.

"There's not too much you can do when the debtor has an unlisted telephone number," says a bill collector with World Wide Collections. "All you can do is send them a letter and hope they respond. Unlisted numbers have made it harder for us to track people down."