Bleep then robo "Are you still there" then dropped (mycell)

Called today. ID read DEFSECURE. No message left.

I answered with a very heavy accent "allo, allo, no reply.
I now answer phones that have a name, and say I am from the Fraud Division of LVMPD and I am a police officer. That gets them off fast!

Another run of the mill "see if anybody picks up" test. If you pick up, the robot software records that there is somebody at the line and will notify the owner to sell the number.