[jlgreco]

Frankly I am stunned that carriers even let those through in the first place. Has there ever been a person in the history of telephony who wouldn't prefer it if they could never receive calls from unknown numbers?

Then I remember that call centers probably rack up huge phone bills...

[zurn]

Many countries ban phone spam or have a centralised opt out list. A good side of the regulated telecom world.

edit: replying to comment below, many countries have working opt out lists.

[jlgreco]

I want to know why unknown number, regardless of actual origin (spam or otherwise) is even permitted to go through PBXes or the like. Why isn't everything in the network, including my phone, set to drop "unknown number" calls right on the floor?

My phone should be saying to itself "Hold on a second, am I about to turn on the buzzer and display the text "Unknown caller" to the users? /dev/null it."

[zurn]

Privacy/anonymity is a basic feature of any useful personal communication mechanism as I hope you know. Snailmail supported it before the phone network, and the internet supported it after the phone network. Though maybe people have forgotten now that they've moved en masse to things like facebook (<rant elided>...)

Maybe people don't know how to select this feature when they make calls? At least in GSM based networks you can select it on a per call basis when dialing (#31# prefix).

Eg. calling in anonymous tips to your local newspaper, communicating with an annoying company you don't want calling back, etc.

[nutanc]

The centralized opt out list does not work. We have a centralized "Do Not Disturb" (DND) list in India and it does not work. The marketers always figure out loopholes in the system.

[devcpp]

Not with the ban system. Here in France, you can report companies that make automated phone calls and they get strongly punished. I haven't received one in years.

Of course, sometimes I get calls from actual humans for polls or advertising a product, but it's much less of a bother since it happens less often and you can reject them.

[s_henry_paulson]

90% of my unknown calls are people Skyping me. I have no desire to block them.