Imagine how great it would be to have a telephone that didn't accept those annoying and illegal commercial robocalls.
Hermann Wolz of La Conner, Wash. doesn't have to imagine. He's one of 25,000 people who now use Nomorobo, the free service that spots robocalls, blocks them and automatically hangs up.
"It's easy to install and it works real well," Wolz said. "I noticed a change right away."
Nomorobo launched about three months ago by Aaron Foss, a Long Island software developer. The cloud-based technology works for people who have Internet-based VoIP phone service. Last year, Foss won the Federal Trade Commission's Robocall Challenge, which came with a $25,000 cash prize.
He promised his call-screening service would work, but there was no way to be sure until it went public.
Nomorobo websiteSource: Nomorobo
"We are now blocking 48,000 robocalls per week and getting tons of positive feedback," Foss said. "The demand has been absolutely amazing."
How does it work?
Nomorobo uses a service called "simultaneous ring" that is provided by most VoIP phone companies. This feature allows customers to have numerous phone lines ring at the same time.
If your phone company offers simultaneous ring and you sign up for Nomorobo, all of your calls will also go to Nomorobo's computers. The company uses caller ID and call frequency information to screen them.
When Nomorobo decides a call is a robocall, it hangs up after the first ring. That's how you know a call was blocked.
(Read more: Robo this! Service aims to block annoying calls)
"The phone rings once and then it just magically stops," said Eric Giers, a business owner in Milford, Conn. "And then you just smile and say, 'I got ya.'"
Giers has four business phone lines. Before Nomorobo, they were constantly ringing with robocalls. Not anymore.
"It's incredibly peaceful here," he told me. "It's like a gift from heaven."
You don't need to have caller ID on your phone for this to work and Foss promises the information he collects is anonymous to protect subscribers' privacy.
There are currently 1.2 million phone numbers in the company's database of blacklisted phone numbers. These known robocallers come from complaints filed with state and federal regulators.
Software developer Aaron Foss, who won the FTC'S RoboCall Challenge in April, plans to offer a free blocking service soon.Source: Aaron Foss
The system isn't perfect. Robocalls do slip through. Foss encourages subscribers to report those numbers so they can be added to the list. It's crowd-sourcing to stop illegal telemarketing.
Nomorobo expanding … sort of
Anyone with phone service from Comcast and Time Warner Cable can now use Nomorobo. The two cable giants started offering Nomorobo a few weeks ago because they know their customers hate robocalls.
"We are excited about providing our customers with another alternative to block telemarketers and robocalls," said Patti Loyack, vice president of broadband voice for Comcast cable.
(Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.)
Jeff Lindsay, general manager of Home Phones at Time Warner Cable, said, "The last thing we want is for someone to have their enjoyment of our service affected by these nuisance calls."
(Read more: Consumers have had enough, 'rage survey' says)
Nomorobo still does not work with any traditional landline phone service because they don't offer the simultaneous ring feature it requires.
The landline companies say they support Foss, but are limited by their older technology.
"It would be like trying to provide digital service on an analog TV. It just can't be supported," said Kevin Rupy, director of policy development at the United States Telecom Association (USTelecom).
He said traditional phone companies have to be very careful about how they address the robocall issue, because they are governed by regulations that do not apply to cable companies and other VoIP phone services. For example, the FCC requires them to complete all calls and specifically prohibits them from blocking any calls.
"We're not kicking the can down the road, we're not punting on this issue, but we have to be very cautious about how we implement any type of service like this," Rupy said. "It's an extremely complex technological and legal issue."
The industry is making a massive and expensive switch to Internet-based voice technology which would support a Nomorobo-type service. Rupy points out that many phone companies that offer VoIP service (such as AT&T U-verse and Verizon FiOS) are already compatible with Nomorobo.
He said phone companies are working to create standards that would solve the robocall problem for all types of telecommunication networks. "There is hope" for people with landline phones, he said, but a solution is probably one to two years away.
(Read more: Hate robocalls? Here's how you can block them)
Sen. Claire McCaskill, D-Mo., chairwoman of the Senate Subcommittee on Consumer Protection, doesn't want to wait that long.
"It's time for the telecom industry to do its part to help combat illegal robocalls," McCaskill said in a statement. "Nomorobo and other technologies offer consumers greater options to combat this problem, and it's disappointing that these solutions have not been embraced by our phone companies."
McCaskill said it's become clear that Congress must act to "provide regulators with a robust set of tools to fight these fraudsters." She plans to introduce legislation to do that in the coming weeks.
Note: Nomorobo does not work for wireless phones, but there are a number of robocall blocking apps are available for Android devices, such as PrivacyStar, mrnumber and Blacklist Plus.
—By CNBC contributor Herb Weisbaum. Follow him on Facebook and Twitter @TheConsumerman or visit The ConsumerMan website.