Mar 5, 2016
Received two sets of three successive calls today. Nine hours apart. No message left. I did not pick up because I have received several sets of three successive calls recently on my three different lines, all with no messages left, and suspect they're from bots trying to establish whether the called number is active.
All these recent three-successive calls were from the 732 area code, which is the area code of my three lines, so maybe it's not bots, but just a coincidence.