How could we design a Captcha equivalent for phone spam?

Before your phone rings, have a voice say some numbers and have the caller dial those numbers.

Of course, people can develop software to listen and dial the numbers, but maybe if we add different voices/accents it can get harder.

Edit: You’d want white lists so that your friends don’t need to do this.

There’s already services which force you to say your name, and then it plays for the other end before they decide to pick up the phone. My sister had it.

It’s really, really annoying for the caller.

With the spam laws on cell phones, I think this will be less and less of an issue as landlines go away.

I also think Google Voice handles this as well.

You can set up your google voice to require the caller’s name only the first time they call. After the first call, it remembers the number and passes them through.
Or, how about an answering machine that says “Press 2 for Jim, Press 3 for Mary.” I’ll bet that would slow it down a bit.

@worriedguy In that case, what do I do if I’m calling for the first time?

How about when captcha works. It often does not recognize the correct answer.

We need an answering machine that works with caller ID. If a calling number belongs to somebody you know, they get rung through or a polite greeting. If it’s got a toll-free number or no number (sure sign of phone spam), they get cut off. I find it astonishing that answering machines don’t have this feature already.

I am thinking only of something that will separate real people from bots, not strangers from friends. I don’t want to avoid calls from people just because they’ve never called me before. I want to avoid calls from nonpeople.

But the curiosity that prompted this question was just this: what show of evidence could be programmed that would work in a voice medium as Captcha works onscreen?

In the details I specified something not based on phone numbers. Anything based on phone numbers requires prior arrangement. I am thinking of something ad hoc, like Captcha.

I will be the last person in the U.S. to give up my land line. I think that loss of infrastructure is almost as dangerous as the loss of print newspapers. The more we load onto the same grid and link to the same system, the more vulnerable we are to a total loss of communication and the power to fight back. Doesn’t anyone else worry about this?

@Jeruba Thats why I said have it read off random numbers and require the person to type them in. Any person can do that, a bot can’t (or at least, just like regular captcha, it will require some work).

I’m not sure how this connects to the rest of your statement about using a single grid, but yeah, a lot of people are worried about it. I read a book a while back that discussed this (can’t remember what it was). As far as I know, there are people trying to work on the problem. Luckily, I don’t think the grid is as connected as it looks. If you take down a part of it, the rest can adapt (given some time perhaps). There isn’t, as far as I know, one “central internet” or “central cell phone place.”

I agree with roundsquare on the whitelist. If you had this service, I would never call you. Ever.

As far as cutting off toll-free numbers, I’d avoid that. What if it was, say, a family member overseas, calling from an international calling card?

@Jeruba I admire your desire to fight the system. Cell phones do make it easier, and traditional media are good to hang on to, but keep in mind everything’s traceable. Big Brother is watching you. I’m serious.
Actually, it’s more like Big Mother.

In 2009 German Federal Council adopted the “Act against unsolicited commercial phone calls and improvement of consumer protection.” According to the Act, violations of the existing prohibition on unsolicited commercial phone calls can now be sanctioned with a fine up to € 50,000. In addition, the Act clarifies that a commercial phone call is only lawful if the recipient has given his or her prior explicit consent to receive the call. The provision is intended to prevent the caller’s reliance on consent that may have been given by the recipient in a totally different context or after the call was placed. Further, those placing commercial phone calls may not suppress their phone number or identity. Violations of this prohibition may be sanctioned with a fine of up to € 10,000.

I must say it made a difference. We only get at most 10% of unsolicited commercial phone calls after the law was passed.

@Jeruba
I am not worried about the loss of the phone infrastructure. I believe if we did away with the cost of the phone infrastructure a small fraction of that money could be used to increase reliability of the Internet and achieve the same net-reliability results. For instance, I have always wondered why the government did not sponsor a FREE satellite based Internet connection for anyone who wants one. The total baud would be divided by the number of devices. You could always communicate with any other person on that network at a low speed so long as your device, their device, and the satellite were working. If such a connection existed it would be used everywhere for drink machines to send back when they need refilling, for cars to send back their GPS location to the owner’s phone, for people to text message for free, etc. The high cost of a connection for sending tiny amounts of data prevents an entire range of products from existing.

All it takes is for the source of electricity to be compromised, and all those wonderful things that plug in become useless. Battery power runs out, and backup generators can’t sustain the whole works. As long as the phones run on a different system, there is at least some possible communication.

The more things that are linked together in one glorious undifferentiated electronic infrastructure, the more vulnerable every individual component is. Take out one major network service provider’s server farm somewhere, and how much goes down with it?

The old adage “a chain is as strong as its weakest link” should not be forgotten while we’re feeling so invulnerable. We take electrical power for granted, but some of us in California remember what the blackouts were like a few years ago when Enron was working us over—a small taste of the real possibilities.

@unused_bagels, I was not speaking of fighting the system. By “the power to fight back” I was referring to defending ourselves in the event that some hostile force—or some natural disaster—did push the right button or kill the right process and black out all those things that are so conveniently linked together in any part of the grid.

If it is possible to pick up the signal of a recorder coming on-line or an auto-dialer hooked to some sound device and cut that off, that would do it, I think.

Where is Tim Trueman when he is needed?