I think I saw or read something about the robo calls -I'm guessing those are the ones that are computer dialed- are not covered by 'do not call' because a person is not the one dialing.
I think the robo calls will dial up to 5 phone numbers at a time and when the 1st one to answer picks up it will drop the other 4, so I wait until the 2nd or 3rd ring. But I still get some calls with people on the phone, and they may be ones that have a system that just calls one number at a time. My favorite one is the 10th call from the company that states this is your final opportunity for us to call you... Did they become a new company overnight because I'll get one the next day.