Even in an age when everyone has Caller ID on their cellphones and landlines, when more than 200 million numbers are listed on the national Do Not Call Registry, our phones are still inundated with unwanted auto-dialed and prerecorded calls. And though state and federal regulators regularly shut down illegal telemarketing operations, it can seem like a game of Whac-A-Mole, with new robocallers popping up to replace the old ones.
There are a number of ways to use technology to reduce the number of annoying robocalls you receive, but U.S. phone companies have generally left it up to consumers to defend themselves against the telemarketing onslaught, rather than implementing ways to prevent most robocalls from getting through in the first place.
Pre-empting unwanted calls was the intention of the Do Not Call list — shifting the burden to telemarketers to not bother consumers in the registry — but most irritating robocalls are done by scam artists or fly-by-night businesses that don’t really care whether or not you asked to not be called.
Consumer complaints about unwanted calls dominate gripes filed with the Federal Trade Commission every year, and not just because folks are being interrupted in the middle of watching Jeopardy. The FTC estimates that $350 million a year is lost to phone scams.
A new report [PDF] from our colleagues at Consumers Union looks at the various ways phone companies could be proactively trying to rein in robocalls — if they ever get around to it.


Nomorobo was the winner of the FTC’s first competition to create a viable service for blocking robocalls.
It’s a filter — no device needed — that creates a “blacklist” of phone numbers reported to the FTC as Do Not Call violators, and numbers that consumers indicate are connected to robocallers.
Right now, Nomorobo only works on VoIP telephone service; not good for those still on traditional landlines or who have gone cellphone only, but great for the millions of Americans who get their landline service through their cable or Internet provider.
When someone calls your number, Nomorobo rings simultaneously on your home phone and on the Nomorobo servers. If the service IDs the incoming number as a robocaller, it ends the call after one ring.
In an effort to gather more likely robocall numbers, Nomorobo also collects information about phone calls made to numbers that were abandoned after receiving too many unsolicited calls. Since the only people calling these numbers are probably going to be robocallers, this system is able to add to the Nomorobo blacklist.
One of the problems that comes up all the time with tracking down robocallers is “spoofed” numbers — when the info that shows up on your Caller ID has nothing to do with the person calling you.
Spoofing is not, by itself, illegal. In fact, there are justifiable, good reasons — like preventing a stalker or an abusive spouse from knowing your location — for wanting to hide your information. It’s only when spoofing is used to commit fraud or otherwise perpetrate a crime that it becomes illegal.
Nomorobo owner Aaron Foss says his algorithm can help ID spoofers by identifying reporting trends from the service’s users.
“A robocaller might spoof a random number but when that fake number starts calling 5,000 people in an hour, well, humans don’t call like that,” he explains.
If a legitimate caller is flagged as a potential robocaller, that caller will have to enter a number to prove they are human before the call can be connected.
This feature may be a minor impediment to major telephone companies implementing Nomorobo or something similar. One of the telecom industry’s most common arguments against proactive, widespread robocall blacklists is that they might inadvertently block allowed robocalls, which include school closing notifications and emergency alerts.
Moffat says Nomorobo addresses this concern by whitelisting these numbers so that they are not blocked by the “prove you’re a human” numerical code requirement.


Primus — not the band behind Pork Soda (though that would be awesome) — is an independent Internet and phone provider for hundreds of thousands of folks in Canada. It’s also the company behind something called Telemarketing Guard, which Primus Canada has made available to its customers for free since 2007.
The Guard is a filter that aims to head off blacklisted numbers so that they never ring on your end. If a number has been identified by some users as a robocaller, but the verdict is still out, the number is greylisted, which has two facets. First, the caller is asked to press a number and say their name before the call is put through. If that happens, then the recording of the caller’s name is played for the recipient, who then can decide to answer the call, block the number, or have it go to voicemail.
Primus says the Guard has not just cut down on annoying calls to consumers who use it, but that offering the service has made good business sense for the company because nearly 9-in-10 Primus Canada customers have cited the Guard as the main reason to retain their service.
In 2013, in response to a Senate committee question about why American phone companies had not adopted the Primus Canada Guard or Nomorobo, trade group USTelecom mentioned [PDF] that Nomorobo can block calls because it’s not a phone service provider, and Primus — owned by a Virginia-based company — is only using the Guard north of the border, possibly because FCC rules would have forbidden the company from using it stateside.
But as noted in the Consumers Union report, the FCC said earlier this year that it’s okay for U.S. phone service providers to offer services like these.


“The phone companies could be doing so much more to stop robocalls from harassing their customers,” said Maureen Mahoney, Policy Analyst with Consumers Union and author of the report. “But so far they’ve just been passing the buck and making excuses.”
According to the report, the major roadblock to putting robocall filters in place is the phone companies’ inaction.
Nomorobo’s Foss says his VoIP call-filtering system could be used on landlines and wireless phones; it would just require the phone companies to switch on simultaneous ringing for these types of lines. However, he acknowledges that old copper-line networks — some of which have reportedly fallen into disrepair — may not be up to the task.
Henning Schulzrinne, former Chief Technology Officer of the FCC, echoes this sentiment in the report, noting that, “Older landline systems may not support simultaneous ringing or carriers may choose not to enable the feature.”
USTelecom contends that even if you got it Nomorobo to work, “it is not clear whether it could be accomplished while still being able to offer a… solution on a cost effective basis to end users.”
It’s understandable that telecoms would want to remain neutral with regard to call-blocking. By doing nothing, they can avoid the potential problems that could occur when an important, legitimate emergency call gets blocked.
But a look at the numbers shows that something has to be done to curb these calls. In addition to the huge volume of complaints filed with the government every year, more than 550,000 people have signed on to Consumers Union’s End Robocalls petition asking AT&T, Verizon, and CenturyLink to give customers the ability to block these calls.
“Robocalls are more than just a nuisance,” explains Mahoney. “They can cost consumers real money when they are used to commit fraud. It’s clear that the technology exists to dramatically reduce these unwanted calls. Now it’s up to the phone companies to show they are serious about solving this problem by offering free call-blocking tools to their customers.”

Editor's Note: This article originally appeared on Consumerist.