Cid said "Caller Unknown".

Have received calls from this number, as well as 206-539-5645. Called the numbers back and got recording "Sorry, all circuits are busy right now. Try calling back later."

Same as "tired" above, no message, called twice in a row, on the 2nd pass I fed 'em to the CPR. These people must be the stupidest, most inept, badly dressed and foul-breathed imbeciles on the planet if they think WE won't win the battle against home invasion...

The "caller" is not actually a person but is a series of recordings, connected to voice recognition.  The software makes statements in response to what the recipient says. Very clever.

this person calls and wants to speak to head of household and then hangs up