Robocalls are unstoppable – 3 questions answered about why your phone won't quit ringing

February 26, 2019 by Raymond Huahong Tu, The Conversation
Caller ID won’t always tell you it’s a robot doing the dialing. Credit: LightField Studios/

When your phone rings, there's about a 50 percent chance it's a spam robocall. That's not probability – it's what the U.S. government agency regulating telecommunications says. U.S. mobile phone users received 48 billion robocalls in 2018 alone – more than 100 calls per line.

Raymond Huahong Tu, a computer scientist at the University of Maryland who has researched the technologies and practices of robocalling, explains more about these annoying parts of everyday life – and why they're so hard to avoid.

1. Why does everyone get so many robocalls?

Advanced automatic dialing systems make it easier and cheaper for small operations to generate huge numbers of calls. Robocalling can dial many phone numbers at once, and play a prerecorded or computer-generated voice message to anyone who answers. A person running a operation just has to set up the system and let it run. The program will call mobile phones, homes' landlines, businesses and just about any other number – either randomly, or from massive databases compiled from automated web searches, leaked databases of personal information and marketing data.

It doesn't matter if you've signed up with the federal Do Not Call Registry, though companies that call numbers on the list are supposed to be subject to large fines. The robocallers ignore the list, and evade penalties because they can mask the true origins of their calls. The autodialing programs encode Caller ID information that makes the robocall look like it's from a local number, the Social Security Administration or even your employer's head office. That means it's harder to ignore the calls – and much more difficult to identify who's actually calling.

The calls keep coming because robocallers make money. Partly that's because their costs are low. Most are made and connected via the internet, so robocall companies can make tens of thousands, or even millions, of calls very cheaply. Many of the illegal robocalls targeting the U.S. most likely come from overseas – which used to be extremely expensive, but now is far cheaper.

Each call costs a fraction of a cent – and a successful robocall scam can net millions of dollars. That more than pays for all the calls people ignored or hung up on, and provides cash for the next round. Casting an enormous net at low cost lets these scammers find a few gullible victims who can fund the whole operation.

Not much help anymore: the National Do Not Call Registry. Credit: The Conversation screenshot of FTC website., CC BY-ND
2. Why is it so easy to fake the Caller ID info?

The current Caller ID system relies on the phone – or computer system – placing the call to tell the truth about its own phone number. This is an artifact from the early 1990s, when Caller ID services began. At that time, the in the U.S., as in most countries around the world, was a closed system served only by a small number of trusted telephone companies like AT&T and MCI.

Today, of course, the phone system is open to the entire world, with thousands of companies offering telephone service over the internet. The international telecommunications standards, though, haven't kept up and don't yet offer a way to police a system in which mutual trust is not enough to guard against Caller ID abuse.

My own research has worked to develop a standard method of authenticating the Caller ID information. That system would let call recipients be more confident scammers weren't disguising their phone numbers.

In the meantime, the U.S. Federal Communications Commission has been asking U.S. phone companies to filter calls and police their own systems to keep out robocalls. It hasn't worked, mainly because it's too costly and technically difficult for phone companies to do that. It's hard to detect fake Caller ID information, and wrongly blocking a legitimate call could cause them legal problems.

3. What can I do to stop getting robocalls?

The best approach is to protect your phone number the way you do your Social Security and credit card numbers. Don't give your phone number to strangers, businesses or websites unless it's absolutely necessary.

Of course, your may already be widely known and available, either from telephone directories or websites, or just because you've had it for many years. In that case, you probably can't stop getting robocalls. My advice for dealing with them is to stay vigilant. Don't assume the Caller ID information that pops up for an incoming call is accurate.

You could, for instance, not answer the call and see if the person leaves a voicemail. Or you could ignore the call and dial the number it came from yourself – connecting you to the real person or organization the call pretended to come from. Lastly, if you do answer the phone, don't assume the caller is telling the truth. Ask questions to help you determine that they're legitimate – or not. And hang up if you have any doubt at all.

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2 / 5 (1) Feb 26, 2019
Phone companies need to enable a bogus call or text feature that lets us flag any call or text received as malicious. If the originators or such calls have an overwhelming percent of flagged connections, they are not welcome to connect anymore. We can't trust the automated systems so it is time to create a user-driven one.
2 / 5 (2) Feb 26, 2019
First of all don't allow robo callers change the name and number that their phone displays when calling.

Second have a federal no call list and give the people who are called the legal means to sue the callers. A $10,000 judgment in civil court should stop them in their tracks.
3 / 5 (1) Feb 26, 2019
Best yet, switch to a private unpublished number and never answer calls from phone numbers you don't know.

This is how I've avoided phone spam for nearly two decades. And it works.

My phone line is notoriously quiet. same for my cell number. I simply don't hand that info out to just anyone.
4.5 / 5 (2) Feb 26, 2019
KBK I am not so sure that the Robo callers don't just dial random numbers so unlisted or not does not really matter. Also if one needs to have and answering machine they are out of luck.
5 / 5 (1) Feb 26, 2019
You can buy phones now that allow you to require that any caller not on your whitelist has to press '#' before being connected. That eliminates robocalls. I suspect eventually the robots will learn to press '#'. So, it's a temporary fix, albeit highly effective.
2 / 5 (1) Feb 26, 2019
Would it be possible to charge a flat monthly rate for normal phone usage then charge extra for high volume users making it unprofitable for the spammers?
not rated yet Feb 26, 2019
1. Technical steps need to be taken to have verified Caller ID. (This will sadly take time.) Right now, I think those call blockers that use crowd sourced list of telespamming numbers are dangerous. Too much spoofing going on. Just last week we had a call with the faked number of a neighbor.
2. Do Not Call List needs to be expanded to have Non-profit & Political (polls) options. I'm tired of electioneering occurring on my phones! And anybody who thinks about it for a moment would never answer questions on call from someone claiming to be a pollster. Into what databases is that info going. On the occasions I've gotten a name of the polling organization, I could not find them on a web search.
not rated yet Feb 26, 2019
I'm beginning to think that until we have solid caller ID, we need to reverse strategy. If you have time and can safely do it, answer all those odd calls and press the button to talk to the bastards! Then tie them up as best you can:
- just lay the phone down
- play music
- pretend to be a kid
- pretend to be interested but dim-witted or hard of hearing
- ask a lot of questions about their product - try to get identifying info
- "Dave's not here man!"
- cuss them out
- feed them bogus info (being careful that non of it could be valid for somebody else)
- other ideas?
They may have automation that places millions of calls quickly and cheaply, but they don't have the humans to deal with anywhere near that call volume. They rely on [tens of ?] thousands of calls being unanswered/hung-up on to screen them out from the handful of calls where a sucker bites. If the filter burden shifts to the operators, they will be swamped. It will destroy their operating model.
not rated yet Feb 26, 2019
@Jeffhans1: Caller ID spoofing renders block lists based on offending numbers useless. In fact it's dangerous. I've seen real numbers come up on multiple occasions, including a neighbor's recently. With this kind of scheme in play, the use of someone's legitimate number will effectively be a denial of service attack on them.
@MR166: can't really do this until the spoofing problem is solved.
@bobsage: Maybe next step is to ask a math problem. What if you have more than one extension? Does it work then? I've considered setting up a little PBX as a call filter.
not rated yet Feb 26, 2019
3. Landlines deserve the same kind of legal protection against robo calls that cell phones have.
not rated yet Feb 26, 2019
@MR166: I like the right of private action. This is the time of year when little podunk lawn care guys call. I'd love to be able to record their call and after their pitch I say "You have violated the do not call list. Please send me a check for $500 or I'll see you in small claims court."

Last election cycle, as before, our local sheriff was recording robo calls for local GOP candidates. I caught one coming in from out of county and called that number back. It was a disconnected number. Imagine that, the sheriff calling from forged numbers! I wish I had a video of answering that one. I would have been quite entertaining to turn it over to the local news stations...
5 / 5 (1) Feb 26, 2019
@MR166: I like the right of private action. This is the time of year when little podunk lawn care guys call. I'd love to be able to record their call and after their pitch I say "You have violated the do not call list. Please send me a check for $500 or I'll see you in small claims court."

Last election cycle, as before, our local sheriff was recording robo calls for local GOP candidates. I caught one coming in from out of county and called that number back. It was a disconnected number. Imagine that, the sheriff calling from forged numbers! I wish I had a video of answering that one. I would have been quite entertaining to turn it over to the local news stations...

You know what to expect this year. Get your recording setup ready now and enjoy the hilarity that your evidence will cause these law violating officials.
4 / 5 (1) Feb 26, 2019
Put a legal $10,000 bounty on their heads and this will stop overnight. I can see the TV ad now.

Are you a victim of robo-callers? Just call Dowe-Suem and Howe for a free consultation.
not rated yet Feb 26, 2019
The problem is finding the bastards. Between VOIP connections from anywhere on the planet and number spoofing, it is really hard to track these criminals down. Maybe if there were some * or # code one could enter after a robo call, the phone company could latch some deeper info about the call and report it to the feds. Perhaps those who provide gateways for forged numbers could be held accountable.

As you can see, this is a hot button issue with me. I see I've made a few typos in my posts above, most seriously, inadvertently referring to those who handle responses to robo calls as 'human'. I apologize profusely for that error.

not rated yet Feb 26, 2019
CU it should be relatively easy to find them. They are trying to sell you something and thus need a bank account.

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