Series of 'Fax' calls, started with (02) 8043 9242, then immediately after hanging up, another from this 07 number , again with (07) 3523 4514, and AGAIN with (07) 3523 4552 (which we diverted to VM, and this seemed to slow the 'onslaught'), then after several minutes (02) 9157 2889 (which we put on Hold till they hung up - and again, no immediately getting another one), and AGAIN after several minutes (02) 9157 2800 (which we again put on hold .. this time they didn't hang up before the 'call wait alert' buzzed, and call still in progress so we put on Hold again and THIS time they hung up after a few seconds - SO YOU KNOW, someone IS at the other end orchestrating the harrassment! ) ... various Reddits and Google results hypothesize it's scammers trying to get your Cell/Mobile 'Wallet' to react/open in response to the Fax/CED tone .. but others disagree ... others wonder if it's to access your computer wirelessly by connecting to a wireless fax .... the putting the calls on Hold seems to deter the perpetrators anyway ...