It’s nothing short of a dream come true — a service that blocks unwanted robocalls. Best of all, it’s free and available now for many VoIP customers.

Developed by a freelance computer programmer, the Nomorobo (No-More-Robo [Calls]) system was launched last October, the result of a Robocall Challenge contest sponsored by the Federal Trade Commission (FTC (News - Alert)) to deal with illegal robocallers who tend to interrupt dinner with unwanted solicitations.

So far, Nomorobo seems to be working where the FTC’s Do Not Call Registry has not. The system uses a simultaneous ringing feature available on most VoIP systems. After a user signs up for the free service, the system will answer a rejected call and then hang up on the robocall before the home or office phone picks up.

The service compares the incoming call to a blacklist of illegal telemarketers and robocallers, which is compiled from complaints. If there is a match, Nomorobo will stop the call after the first ring. If an unwanted call gets through, users can report them to get blacklisted. If a legitimate caller is mistakenly identified as a robocaller, the service has a verification process.

“We’ve blocked over 2.5 million robocalls and there are over 90,000 people using the system right now,” said Aaron Foss, developer of Nomorobo. He earned $50,000 from the FTC for his invention.

Users can sign up at Nomorobo.com. The system reportedly still allows “good” robocalls from a doctor’s office or school district to go through. However, the service is only available for customers using their cable company’s VoIP service. Foss plans to work with additional carriers to make Nomorobo available for wireless and landline phones as well.

The Federal Trade Commission estimates 20 percent of all incoming calls nationwide are robocalls. The agency fielded more than 2.2 million complaints about robocalls last year.