Spoof dialer... an automated system looking to see if a voice picks up and responds.... they hope to hear you say "Hello?".  If so, that puts your number on a dialer list that is sold to marketers...  This is how they make sure they are not dialing a fax or data line.

Did not answer, left no message.  Blocking calls.

Scammers from India

+1 (346) 239-6527  I just received a call from this number.  They called my business line, I answered it and no one responded. Will add them to a blocked numbers.  Not sure why if I am on the do not call registry I get these calls

The DNC doesn't cover Businesses from what I know-plus it's not a call blocker