Jul 25, 2015
What it means is that the number/name on your caller ID has been faked, spoofed, it's not real. Scam artists do this all the time, sometimes "borrowing" legitimate, active phone numbers to display; other times using numbers that are out of service or unassigned.
Being on the DNC list matters a lot. If you understood how it works you'd realize that.
If you're on the DNC list, legitimate telemarketers are not calling you. That leaves scammers, probably from India or Pakistan or any other place. You can practically be assured that any unknown number calling you should be ignored and in the case where they call repeatedly, blocked.