Memo to robocallers: They're out to stop you.

Whether pitching a product or trying to foist a scam, illegal telemarketing and robocalls are a persistent problem. But efforts to cut off the irritating calls are on the rise, from lawsuits to landline tools to cellphone applications.

Last week, one of the newest entrants in the battle launched nationwide. Called Nomorobo.com, it's the brainchild of a Long Island software developer who shared a $50,000 prize from the Federal Trade Commission for the best tech solution to thwart telephone spam.

The FTC, which has been deluged by a growing mountain of complaints from U.S. consumers, is only too happy to welcome the new weapons in the war on robocalls.

"We're aware of, and extremely pleased, that potential technological solutions to help consumers block unwanted, illegal robocalls are making their way to the marketplace," said FTC spokeswoman Kati Daffan. "This is exactly why we launched our Robocall Challenge last year."

Other tech tools are focused on smartphones with applications -- many of which are free -- that let you block known spam callers and do reverse lookups of suspect numbers. Among the free versions are Mr. Number, a Palo Alto-based company, for Android phones and Call Control in Bellevue, Wash., for Android and BlackBerry phones. Like other smartphone apps, they rely on "crowdsourced" lists of spam phone numbers, which are reported and shared by fellow users.

And for the first time, Apple's (AAPL) recently issued operating system, iOS 7, lets iPhone users block unwanted calls.

Clearly, there's a demand for solutions. Every month, the FTC fields about 178,500 consumer complaints about telemarketing and automated robocalls.

The National Do Not Call Registry, which lets consumers sign up their home phones and cellphones, helps block most -- but not all -- telemarketing calls. As of June 2013, the registry's 10th anniversary, more than 221 million numbers were registered.

In the past decade, the FTC has filed more than 100 lawsuits and slapped millions in fines against companies accused of targeting consumers with billions of illegal robocalls. Last year, in one of its biggest cases, it slapped a $3 million fine against a global robocalling operation that bombarded consumer landlines and cellphones with 2.6 billion "urgent" messages that were nothing more than pitches for worthless extended auto warranties and bogus reductions on credit card rates.

Deluged by millions of consumer complaints, the FTC last year turned to the private sector, announcing its Robocall Challenge contest, seeking entrepreneurs such as Foss to come up with solutions. More than 800 entrants sent in submissions.

Since Nomorobo was announced in April as a co-winner of the FTC's contest, nearly 23,500 consumers signed up to be included in its launch, Foss said. (The FTC's co-winner, Serdar Danis, who offered a similar solution, was unable to be reached for comment.)

Foss' technology relies on consumers enabling a specialty feature in their phone system that's called "Simultaneous Ring," "Locate Me" or other names. Basically, it allows customers to have incoming calls ring on all their phones at the same time, allowing them to pick up wherever it's convenient. Foss piggybacks on that phone feature, using Nomorobo to screen incoming calls.

When linked to the user's phone, Nomorobo "answers" the call first, screening it instantly against databases of numbers known to make illegal robocalls, as well as using algorithms that detect whether it's a number-dialing at unusually high volume. For instance, when the same number has made 5,000 calls to different numbers in the past hour, it's a red flag. If a robocall is detected, the call is automatically disconnected, before the consumer's phone even rings. Those numbers go onto a "black list."