Silent handler for nuisance calls?

[Somnolent]

Seems to me that it ought be possible to have some simple little gizmo on your phone line that mimics one of those smart PBX systems & intercepts incoming calls with the appropriate voice prompts, audible only to the caller...

If your call is about home improvements please press 1
If it is about malware on a computer please press 2
For lifestyle surveys & market research please press 3
-etc
-etc
-etc
For other unsolicited calls please press 8
To leave a message please press 9 

And then only if 9 is pressed does the call go through to the regular equipment with a normal ring tone/ answering machine etc.
Anybody you'd actually want to speak to would know to press 9 immediately.

Probably some BT or ofcom rule says you can't do this, so no one has produced a commercial version.
Must be possible on a Rasberry Pi though?

[rafletcher]

It seems to me that most nuisance callers aren't prepared to wait for long - and in that respect the BT Call Guardian works perfectly well. We've not had one nuisance call come through since I bought our new phones with it built in.

[fuaran]

Something like TrueCall? https://www.truecall.co.uk/

[Hot Flatus]

I've got a BT Phone that does it. Got a 2 pack wireless answerphone set for £40. Probably can get them cheaper.

I can confirm that nuisance callers dont like it.

[Canardly]

A simple answer phone has reduced our spam significantly.

[Si S]

A simple answer phone has reduced our spam significantly.

Yep, anyone willing to listen the entirety of Pink Floyd's Welcome to the Machine, probably does actually want to speak to you

[Jaded]

Something like TrueCall? https://www.truecall.co.uk/

I've got experience of Truecall with a relative. I program in numbers for her from the web interface. The system works reasonably well, although the recorded messages are not great sound quality.

[clarion]

A simple answer phone has reduced our spam significantly.

Yep, anyone willing to listen the entirety of Pink Floyd's Welcome to the Machine, probably does actually want to speak to you

Or wants to listen to Welcome To The Machine

You've been in the [telephone] line, filling in time...

[De Sisti]

Many of the nuisance calls are automated and are voice responsive (at least some of the ones I've experienced).
If you don't say anything when you answer the call it will terminate after a few seconds.

[Kim]

You can do that sort of thing in Asterisk, and Asterisk will run on a Raspberry Pi.

My approach is to give unrecognised callers a burst of SIT (which causes most spammers to drop the call and remove you from their database), followed by a "press 1 to continue" Turing test (if they pass, it rings the phones, if they fail, straight to voicemail).  Repeat offenders get sent straight to the Rickroll extension.  Numbers belonging to barakta's mum and known accomplices ring the phones with a different cadence.  Everything goes to voicemail when we're not at home or in bed (which the computer knows for other reasons).

The bad news is that Asterisk has a fairly horrendous learning curve (the extension language syntax is frankly bizarre), and that getting analogue telephony in and out of a Raspberry Pi is non-trivial:  ATAs are invariably pants, and TDM cards require a PCI slot, which the Pi doesn't have.  Both are horrendously expensive.

In short: Asterisk or similar is an excellent idea if your telephony is already standards-based VOIP.  It's a good idea if you want to learn Asterisk.  It's a hammer to crack a walnut if you want to avoid spam.

[Cunobelin]

We use "BT Call Guardian"

When someone rings they are asked to state name and press #... only then is the call put through with the stated name so you can decide whether to answer

Not a single spam call since it was installed

However I do sometimes miss winding them up

[Steph]

I have a similar BT system, as Flatus describes in a two-pack wireless phone set. It asks the caller to speak. you can hear it and if they are someone you want to speak to, you press 1 and the call is connected properly.

[stu1102]

we use BT Call Protect in conjunction with a BT Call blocker phone

I should say BT Call protect is sufficient on its own to block 99% of most unwanted calls based on our experience

http://home.bt.com/tech-gadgets/phones-tablets/how-bt-is-tackling-nuisance-calls-11364136280225

[Mr Larrington]

I want one that plays this: LAMC ~ Tool

[Cunobelin]

It seems to me that most nuisance callers aren't prepared to wait for long - and in that respect the BT Call Guardian works perfectly well. We've not had one nuisance call come through since I bought our new phones with it built in.

We use this, and it is brilliant

Shame is I do miss winding up the callers..... some of the computer ones could be kept going for ages

[rafletcher]

It seems to me that most nuisance callers aren't prepared to wait for long - and in that respect the BT Call Guardian works perfectly well. We've not had one nuisance call come through since I bought our new phones with it built in.

We use this, and it is brilliant

It is indeed. Despite being signed up to TPS I can see that the Call Guardian has prevented some 17 calls in the last month from non-essential callers, including some with a UK geographic number.

[Cunobelin]

Many companies outsource the calls abroad

These can avoid the TPS regulations

[Vince]

It seems to me that most nuisance callers aren't prepared to wait for long - and in that respect the BT Call Guardian works perfectly well. We've not had one nuisance call come through since I bought our new phones with it built in.

We use this, and it is brilliant

Shame is I do miss winding up the callers..... some of the computer ones could be kept going for ages

Agreed. The one downside is that you need to pay extra for the white list to work.
It should be that people in the phones contacts list should get straight through, but that needs an extra (chargable) option to get the incoming number.

[chrisbainbridge]

But without these calls, how could I practise my acting?  We have had home invasions, alien dissection, multiple homicides, sex, etc. in our house.

[MikeFromLFE]

Live between using Truecall referenced above for a number of years. The system works flawlessly and the number of stupid calls had been steadily dropping - I assume my number gets taken off various databases. Worth every penny.

[rafletcher]

Why pay when Call Guardian is free?  And you create your own white list as you go by using the “always accept” option on first receipt of a call from a new number that you’re happy to get through. 

[Kim]

The fundamental flaw in trying to filter out nuisance calls is that:

a) The NHS like to withhold numbers because they apply 1990s data protection legislation to their 1970s attitude to communication with patients.

b) Large organisations that aren't to set up to propagate sensible DID numbers from their PBX opt to withhold everything so their switchboard operator doesn't spend their life dealing with "You phoned me?" calls.

So you're always going to have to deal with the withheld numbers one way or another.  A Turing test helps.


Similarly, if you give someone a number for SMS purposes, Stupid Hearing People are incapable of not trying to call it.  Not found a good solution to that, because the obvious (outgoing message telling them not to call this number and to text instead) just causes them to leave voicemail, because they're stupid.

[CrinklyLion]

I think that on my phone (possibly my old one, I'm not sure) I had the option to manually refuse a voicecall and send an automated text to the incoming number - vaguely remember messages like 'can't talk at the mo' and 'in a meeting'.  Presumably it would be possible to set up a message saying 'this number is not for voice calls - please text me instead'.  Then the (autopilot conditioned response) message left on the voicemail can be happily ignored and the person has a prompt right there in their hand to which their (autopilot conditioned response) reaction is most likely to be hitting reply on the text?

[Mrs Pingu]

Thanks for the heads up on call guardian - I didn't know it was a thing...

[rafletcher]

The fundamental flaw in trying to filter out nuisance calls is that:

a) The NHS like to withhold numbers because they apply 1990s data protection legislation to their 1970s attitude to communication with patients.

b) Large organisations that aren't to set up to propagate sensible DID numbers from their PBX opt to withhold everything so their switchboard operator doesn't spend their life dealing with "You phoned me?" calls.

So you're always going to have to deal with the withheld numbers one way or another.  A Turing test helps.


Similarly, if you give someone a number for SMS purposes, Stupid Hearing People are incapable of not trying to call it.  Not found a good solution to that, because the obvious (outgoing message telling them not to call this number and to text instead) just causes them to leave voicemail, because they're stupid.

As long as a person is on the end making the call, Call Guardian will work. It initially blocks ALL numbers until you whitelist them. You are correct that of course you can’t whitelist unlisted / withheld numbers, but (and ok, we are talking NHS here) the human caller can hold for 30 seconds after announcing themselves they will get through as you accept the call. But I can see you might not want to risk it.