Automated recorded call saying it's the Australian National Broadband Network and that your phone and internet service will be disconnected if you don't connect to the NBN and then it asks you to press 1 to be connected to a technician. I never press 1. If you just wait and don't press a number, the call soon terminates. I don't know if this is an automated way of fyshing for your IP address if you are already connected to the NBN, but I would advise to never press 1 or any other number if you get such a call. Just hang up.