I didn't answer. "Unknown" was on Caller ID.

I received a call from this number. There was no one there. I tried calling the number back and got a message saying that the subscriber had activated the "do not disturb" feature. I am suspecting some sort of mass-fax-mailing or something of this sort...

Called my mom's uncle and asked for her by her maiden name.  She has been married over 60 years!  Caller asked if he was her sister and he said yes.  Then he asked the lady caller if she wanted her phone number and the woman hung up!

called residential number at 3:40PM
no response when answered
caller hung up shortly after being answered without speaking
called number is on the national do_no_call registry

Called after 5 PM Thursday.
Picked up. Caller ID showed Longview, Texas.
They hung up after 3 or 4 rings.
Being on Do Not Call Register does not seem to matter to "them".