Or just let telephone users set a price, for someone not in there contact list, to call them. Set it at 5 cents by default. Problem solved for the most part. People that don't know you can still call you (like the person who you left your curtains at for repair) but most robo call campaigns won't be worth it. If you really hate spam, set your price to $10.

How would you prove the call was spoofed? Record all calls? Prove it with statistics? No telco will pay. This is a technical problem.

If an incoming call is saying it's coming from 555-1234 and telco owns 555-1234 and it's not one of their authorized income points then the call should get dropped.

Or if they don't own it then it's on who's inserting the call into the system.

Telco systems are fun. And by fun I mean it's a complete mess. ISDN is hard and full of caveats (look at SIP for a taste of what it involves).

You have a call received on your monthly bill from a number and the owner of that number does not have the call on their bill.

How? Even in the same city, cellular and land lines aren't always serviced by the same company. In most places I'm pretty sure it's illegal for phone companies to be swapping call data. Or are you suggesting I call back all the numbers that call me to compare bills with the owner on the other end? This plan is not going to work out.

The courts can deal with things like this.

>> I think the correct approach is economic, not technical.

> This is a technical problem.

IMHO, it's both. Economic sanctions need to be put in place to motivate the telcos to create and adopt robust technical solutions.