You may or may not be aware that Telstra closed its 2G network on the 1st of December 2016. Since this closure all 2G devices no longer work on the 2G network (except select remote areas) using the Telstra service. People can continue to use Optus or Vodafone until those networks are also shut down during 2017.
We upgraded our DIY wireless alarm system in April/May 2016 to a 3G alarm system called The Protector Series II. Meaning our wireless DIY alarm system can operate on the 3G/4G networks.