They call and let the answering machine run, but they don't say anything. There is about a minute of dead air. I think the new thing for them is to do something to have a message logged to get a person to call back. This isn't the only number that does this.
I just got a call from this number, cid says Chesapeake, Va. Right before that I received a perceived scam call from Cincinnati, Oh. I posted that and while I was typing this call came in. You might want to check out 513-449-6771. The back to back calls might indicate they're in cahoots .