I have this....
Several years back I was looking for a call blocker for my landline, since it had started getting irritating amounts of spam calls.
Naturally everything out there was the type where : You press this button and caller iz blocked!!!!
Except, call spoofing. You can press that button a million times and it won't stop a damn thing. Plus.. those type of 'blacklist' devices have a limited memory and once you get past [arbitrary number] just start dropping numbers off.
And, of course - it doesn't actually help. A whitelist is arguably better, but means you have to put 'the plumber, the recruiter, the vets, the diner-where-you-left-your-wallet' on it in advance...
So, after a while and a whole lot of research I found this : https://www.amazon.com/Tel-Lyn...
What IT does is - exactly as you say. If the caller is on a whitelist - lets them through, No questions asked
If they're not, it asks them to provide their name, number, etc etc.. and then it rings your home phone ( doesn't connect them yet) and provides.. their name and number. Press #1 to let them through AND add them to a whitelist, press #2 to let them through this once, press 3# to drop the call, press #4 to send them a nasty message and THEN drop the call.. etc etc etc.
It's fabulous. Honestly, it cut our home phone spam down to exactly 0. What's nice about it, ( and important to me) is that it doesn't ring the phone when a non-whitelisted number rings. The crappy thing I had before this would do that 1-ring before the callerID had been sent, then chirp and drop it. But that single ring was still annoying. This thing... it intercepts the call, does its thing and the phone is silent if the caller never goes through the process...
So, you can see from that Amazon link up there, that it's unavailable. It's been unavailable for years. When I was doing my research, it was unavailable, but I *did* manage to find a web site for them where you could order direct. It was unavailable there too.. It wasn't until I was showing a friend 'This is what I wish I had...' some time later, that I found it had a 'paypal' button lit up, and ordered one right there an then. Since then, though.. it was 'unavailable' again, then went 'retired...' and *now* the web site is completely non-existent. :(
I suspect they got some kind of shenanigans dumped on them. sued, or bought or 'something'. A product this good would never just 'go under' and everything just suspiciously 'disappeared'.
Bloody fantastic device. I sincerely hope mine never dies...