VOIP Tech Chat → How I stop telespammers dead, with voip.ms IVR

I posted this earlier in the TekSavvy forum and thought I would share it here. My approach to auto-blocking telespammers will work on any voip service with a custom IVR (interactive voice response) capability.

My motivation:
Two years ago, I used to get up to six calls a day from telemarketers. I was constantly adding numbers to my block list but new numbers kept popping up, often for the same telespammer.

My solution:
1. My number answers with a message promptly played by the voip.ms IVR: "Please press 1 to prove you are a real person and not Pierre Poutine." (inside joke for Canadians)

This filters all the telespammers who use autodialers to initially connect to a number and only then switch to an agent after it is answered. The agent will not hear the essential instructions because they won't be online fast enough. The agent or ADAD spam recording will get dead-air, time out by voip.ms, and then be hung up on.

2. After 1 is pressed, a second voice recording is played which states quite emphatically that I do NOT donate to or purchase anything from anyone by telephone. Legit charities hang up at this point. (I donate to charities I choose, and I don't want to encourage them or new ones to constantly interrupt my life.)

People with real business or personal callers are asked to press another number to continue, and do so.

3. My phone(s) now rings through. Because the calls are filtered by this point, I can ring both my voip ATA termination and cell phone at the same time without grief.

4. If I don't answer any ringing phone after a timeout, my v-mail answers.

I give a special extension number to people I know who have legitimate reason to call me. They can enter it at step 1 above, and ring me immediately. If they forget it or lose it, or some real person is calling me for the first time, it's no big deal. They only encounter a few seconds more delay.

In the two years since I set this up I have only received one telespam. I have had only amused responses from friends and other business contacts who liked my setup. Who doesn't hate telespam?

It's been a huge improvement. Now I can get my work done without mental interruptions throughout the day, we can eat our meals enjoyably, and not have sleep interrupted by salespersons.

All this required was a little bit of configuration of the voip.ms IVR, and the recording and upload of the two voice recordings referred to earlier. Total time to solution: less than 1 hour. Quality of life improvement: priceless!

Brett

I know exactly how you feel. I use step 1 and it has been perfect so far. I am in front of the phone all day at home and this has made a big difference in how I regard the phone: not having the uncertainty about who is calling, not needing to screen calls and listen to see if it is a real person or a telemarketer robot.

At night, I have voip.ms switch it to request a PIN to ring through. I feel like the phone works for me instead of the telemarketers.

I like it. That is thinking out of the box.

I can confirm this technique works well. On voip.ms I have added a "whitelist" using the CID Filtering option. There I enter the numbers of family and friends who call regularly. On a match, the call goes straight to ring our phone, and bypasses the IVR completely.

My IVR says something like "If you are a friend, acquaintance, please press 1, otherwise please press 2". 1 rings the phone. 2 goes to vm. I have not found the need for a second recording re: donations or purchases. These callers all seem to use robodialers who think they have hit an answering machine and hang up. We've never had one of them leave a message. The robodialers will call back; some of them are quite persistent, but eventually they give up.

This way, our regular callers don't have to do anything out of the ordinary. When you come right down to it, at our home at any rate, there just aren't that many regular callers so the whitelist approach is entirely manageable. Maybe I need more friends!

I had a problem with the MS Society calling. They are very persistent and made calls from several different numbers. I created a call flow to send these numbers to a recording of SIT tones for number disconnected. Three of the numbers reached the recording and then the calls stopped completely.

Interesting, rollerblader7. Thanks for sharing.

I missed the voip.ms whitelist capability, so I will look into that. I need more friends, so it's won't be a maintenance burden now

I received more hand-dialed charitable calls (e.g. United Way type calls. but I would donate to those directly or online so I don't need them phoning me too, or for extra donations). So I found the second filter step to be valuable. Maybe it's an Ottawa-market thing. Or maybe those human calls have dropped off since I implemented this two years ago and it is redundant now.

It would be nice to have instrumentation in the IVR to see where they drop off. I guess that's one reason to set up a full PBX...

Thanks for sharing.

An SIT disconnect recording is a great destination for blacklisted numbers. I use that myself.

Yes, I see this now - and have used it to send some numbers directly to my ring group. Thanks for pointing this out.

It hasn't stopped. I'm almost at the point of sending callers to an IVR. Right now I just add them to the blacklist after every annoying call, a simple *32 from any phone and they are added.

For business use, I have a duplicate copy of the IVR where all extensions go to voice mail.

Anything with a suspect caller-id appears to get the same treatment as a normal caller, except that for some reason nobody is ever available to take their call...

Now if I could only get voip.ms to ignore very short voice mails...

(Great system - I love the Pierre Poutine reference!)

I've never heard of *32.
What does it do?

Blacklist the last caller.

I have a similar setup except I don't forward all calls to the IVR, only those from invalid/anonymous numbers. I also have a similar setup for all calls between 2200-0800 hrs. I need my beauty sleep and hate getting butt-dialed at 3AM

Never had much of a problem with telemarketers to begin with but they're pretty much extinct as far as I'm concerned now.

Is that only for Asterisk?

The big win would be to automatically add anyone who presses '1' to a list of approved numbers, so that the next time they call you from the same number, they don't have to go through that rigmarole.

I have the same "press 1" thing going on my line, but I've gone through and set up a filter that bypasses it for all the people who commonly call me.

One downside of this scheme is that for people not on the whitelist, they start incurring billing minutes before they actually ring my phone, meaning they have to pay for calls even when I don't answer. I am fine with that, because I have that down to a fairly small number of callers. But now and then someone will call me from overseas who is not on my list, because they used a calling card or a dialing service or the CID was otherwise mangled.

I did not include the 2nd part of your setup, where it reads out a blurb to the caller. Just doing the first part eliminated all the calls I ever get, and once I know you are a human, I don't want to waste any more of your time--I want the phone ringing ASAP.

The more intelligence added to the phone system, the better. I don't get many calls, but the easier/faster I can identify them and route them, the happier I'll be. For me, knowing it's from a specific provider or DID via CNAME or modified identifier helps determine whether I should answer or not.

I think I may make my default last resort for many of my DIDs be Lenny. Here's a link to my last Lenny call. I thought I'd find a permalink for my post, but here's the mp3 link instead: »/r0/do ··· ower.mp3

Yes.

 
 This would be an ideal situation for a custom ringback tone/music/announcement (as used by some toll free numbers).

The line wouldn't be 'answered' until a number is pressed or a timeout occurs.

So if somebody presses '1' and the phone rings, but you do not answer, then they go to voicemail (I assume). If you do not have the 'press 1' bit, then the phone just rings and they go to voicemail. Either way, they are paying for the call.

Why are some people receiving so many telemarketing calls? I do not have this problem.

Interesting. And I didn't know about *32. Thanks for sharing this.

I don't know for sure but I suspect there are lists of numbers where someone bought something in the past sold, as they have been for email spammers.

Which puzzles me for all my telespam, because I don't recall doing anything on the phone other than donating to a legit charity (many years ago) or maybe subscribing to the local newspaper in the past. Maybe my number got onto such a list (if they exist - does anyone know?) through theft or wrongful sale of a legit contact list with a biz I have dealt with, or a simple data entry error, changing some elses phone number into mine. Anyway, just guesses.

If there are 'spam target lists' circulating and being resold, then playing the number disconnected SIT might help in reducing telespam overall as some have reported, as target lists are scrubbed of 'inactive' numbers before being resold.

If somebody answers the phone and it is a telemarketer calling, the number probably gets marked down as an active number, and gets on more telemarketer lists. I used to screen calls before picking up the phone and I think it cut down on the number of telemarketer calls.

Now, using the IVR, it doesn't make any difference how many robo-calls I get, since they always get the IVR 'enter 1' message and never ring the phone.

I can concur with you, but not this post. I had several GV numbers which received lots of SPiT calls. Then, I just configured my FS with the mod_blacklist to process all incoming calls on the GV lines to play SiT on all incoming calls whose CIDs are blacklisted. Within a week, there's at least 90% drops on SPiT calls on those GV lines.

BTW, if you wanna implement WhiteList, you can try using this old Perl WhiteList scripts.

To reduce telemarketer calls, you can have one DID which you only provide to friends and family and have another DID you give to everyone else. All calls to the "other DID" can be automatically sent to voicemail.

Not pre-filtering messages that go to vmail doesn't work for me. I had too many human-dialed charity calls and ADADs that would just continue dumping their message to vmail, which wasted my time there.

This also doesn't work for home businesses, like mine where I have to allow anyone to call and reach me.

I'm perfectly satisfied with my current setup, which is why I shared it.
YMMV.
Brett

If I called a business and received your IVR, I would hang up and call another business. Perhaps you already have enough customers. Very cheap answering services are available to filter business calls.

I am perfectly happy with my setup, that is why I shared it.

This is simple the VOIP version of the old challenge e-mail spam systems where the gateway queues inbound messages and sends out a "prove your not a spammer by clicking here" response. Never been a fan, and never bothered to go to the extra effort to get "on the list".