The Federal do-not-call database was supposed to protect consumers from annoying telemarketing calls.  There's only one problem-fraudulent telemarketers ignore the list and make billions of robocalls pitching scams and con games.

The Federal Trade Commission, which receives some 200,000 complaints a month about robocalling, last year held a contest for the best technological solutions.  Aaron Foss was one of two winners among 800 entries.

The service created by Foss, relies on a feature of the phone system known as simultanious ring.  When a consumer signs up on the Web with the service, all their calls are routed simultaneously to one of Nomorobo's online servers.  Before the call even rings at the consumers's end, the service analyzes whether the call should go through or be blocked, based on a vast database of fraudulent calling numbers.

Although Nomorobo's servers currently rely on lists of over 1 million numbers that have already been tagged as robocallers, Foss designed the system to learn.  A new, unknown number that is placing thousands of calls a minute may set off a red flag for example.

The free service is initially available only to customers of five so-called Voice over Internet, or VoIP, services:  Verizon Fios (VZ), AT&T (T) U-Verse, Vonage (VG), Cablevision Optimum (CVC) and SureWest.

Mr. Foss said that he plans to expand quickly if the service proves to be popular.  "There are 500 million phone numbers in the United States and I'd love to have them all." said Foss.