if you speak wello.hello etc. the computer tags your unpublished number whetherb a cell /sat or landline.later a salescall usually arrives.these devices are used to sell products,services or solicit political support.because many only have a cell/smartphone number that is automatically unpublished these devices are being used more frequently albeit somewhat rude but happening.no reason to get paranoid.sumtimes i just say "yea abracadabra" and within minutes the phone rings with a different number on my caaler ID ..kind of neat high tech robocalls i figure..if you say not a word you probably will not get a return call. the robocall machine is calling and analyzing 1000s of calls per hour...relax