The upcoming switch off of the Telstra and Optus 3G Networks has the potential to leave 750,000 people stranded in the event of an emergency with handsets not capable of “VoLTE” unable to make triple-zero calls. For those on the Telstra and Optus networks, there’s a simple tool to find out if you’ll be ok.

Thanks to EFTM Man Cave member Peter, we learned of Telstra’s 3498 SMS number.

Update: As of May, Optus has made the same SMS service available to their customers.

It’s quite simple – you text the number 3 to 3498 as a Telstra or Optus customer, you’ll receive a response that tells you if your phone is compatible with the VoLTE network on 4G.

Testing by other EFTM readers shows that this also works for Belong customers, and Boost Mobile customers – likely because those are subsets of the Telstra network, not independent MVNOs. Aldi Mobile customers report it does not work for them.

When we originally published this article, Optus did not support the 3498 SMS number, but that has now changed, and thankfully all Telstra and Optus customers can check their compatibility fast.

The learning here is – check. And don’t ignore messages from your Telco about 3G shutdown.