Al Ripskis has tried hanging up, asking the government for help, even paying someone to shield him from the calls. But early in the morning and late at night the calls persist, dragging Ripskis from work, meals and sleep.

At the other end of the line is a computerized telephone solicitor. Sometimes it tries to sell him time at a tanning salon. Sometimes it's a merchandise catalogue."There's got to be some way to stop these damn machines," said Ripskis, a newsletter editor who lives here.

Unfortunately for Ripskis and others pestered by the tape-recorded messages, their use is likely to swell before it subsides.

Despite increasingly tough state laws restricting or even banning the machines, telephone sales companies, retailers and fund-raisers are finding the machines - called auto-dialing devices by their makers - a cost-effective way to churn out millions of calls at minimal cost.

One national telemarketing company can generate as many as 500,000 calls a day with its 1,000 dialing machines, numbers that make it a matter of little concern if some people get angry or hang up.

In fact, it is often impossible to hang up on a recorded sales pitch; many of the auto-dialers keep pumping out their message, tying up the line even after the recipient hangs up.

Computerized sales reportedly got their start in the early 1980s after time-sharing resorts, vacation clubs and insurance agencies discovered their benefit as a marketing tool.

The tactic has won popularity among merchandisers in this part of the country only in the last few years, and primarily among smaller companies such as wine clubs and sales catalogues, marketers said.

At least 21 states have passed laws restricting auto-dialed telephone solicitations. And several bills are pending in Congress to regulate the calls. But despite such laws, the calls keep coming, delivering sales pitches, recall notices, even minispeeches from political candidates.

Almost any company can afford an auto-dialing operation. The machines cost about $220 each and require little upkeep or space.

Compared to live operators, who must be recruited, trained, paid and kept happy enough to stay on, "automatic dialing is a lot less expensive," said Chet Dalzell, spokesman for the Direct Marketing Association, a trade group in New York.

And companies that use auto-dialers say they are less intrusive than calls from live sales people.

"A live operator pushes or cajoles," said Susie Blackwell, national marketing director for FMG Telcomputer, a Fort Lauderdale, Fla., company whose auto-dialers pump out a half a million calls a day for philanthropic, sales and political clients, which have included President Reagan and Sen. Jesse Helms.

"There is less animosity on an automated call because it is less uncomfortable. I'm not saying everyone is waiting around hoping to get a call, but we get a relatively close response rate and it is more cost-effective than direct mail," Blackwell said.

Auto-dialers are "a good tool for mobilizing our supporters if a legislative battle comes up and we need to get word out quickly," said Steve Kerekes, spokesman for the National Right to Work Committee, a Virginia-based group that lobbies against union shops.

Some companies that use the machines readily admit they are annoying. Anne Tuxford, office manager at International Shoppers Spree, a Baltimore company that uses auto-dialers to offer its sales catalogues to Washington shoppers, said, "Personally, I don't like anybody to call me. But we use the auto-dialers and they seem to be effective."

They are. Industry spokesman Dalzell said customers respond at higher rates to calls from machines than to junk mail, and the calls are far cheaper, requiring almost no human labor.

A good response rate to a mass mailing is 1-2 percent; live sales calls can win purchases from up to 20 percent of those called. Automated calls, sales executives said, can draw a positive response of 5-6 percent.

Because automated calls can come from anywhere in the country, it is difficult for either government or the industry to know how many calls are being received.

People with unlisted telephone numbers may receive fewer calls, but deleting one's name from the phone book does not free a customer from auto-dialers. The machines can dial systematically every available phone number in sequence, a technique that especially riles some opponents of the calls.

Legislators arguing for limits on auto-dialers in several states have cited cases of hospitals and nursing homes in which computerized calls hit every room in sequence, bothering patients and enraging staff.

More often, marketers buy potential customers' phone numbers from brokers who offer lists such as credit card holders, store customers or voters.

"We have a steady stream of people who complain about computerized calling," said Greg Vogt, chief of enforcement at the FCC bureau that regulates phone service.

But a recent FCC study ended with a decision not to set rules for auto-dialers because "the commission was concerned about the First Amendment issue of restricting the caller's right to free speech," Vogt said.

A private effort to protect people from unwanted sales calls has proved only somewhat effective, said the marketing association's Dalzell. The association's Telephone Preference Service distributes a list of people who have asked not to receive sales calls.

"But we can only reach those marketers that participate in our service," Dalzell said.

Where governments and the advertising industry have been frustrated, a Chicago man hopes to step in. Bob Bulmash, a paralegal aide who got fed up with sales calls to his home, has started a non-profit company called Private Citizen, which encourages opponents of computerized and live sales calls to act.

Bulmash says recipients of unwanted sales calls should charge the offending companies for their time. Bulmash has collected more than $200 from companies that made sales calls to him.

He tells the company that he wants no more calls. If the calls persist, he threatens to sue the company, generally in small claims court. In a dozen cases, companies have sent him money, usually from $20 to $50, to avoid further problems.

"The right to be left alone in your own home is what I'm trying to protect," said Bulmash, who is circulating to telemarketers a list of people who intend to demand compensation for receiving sales calls at home.

Slowly, consumer complaints about the calls are having some effect, according to sales companies and government regulators. Even as the auto-dialing technology becomes more advanced and prices tumble, Maryland's law, for example, "has cut down quite a bit on automated recorded calls," said Brenda Herman, account executive for Working Phones, a Rockville manufacturer of telemarketing machines.