
Travellers visiting Australia may now find themselves blocked from local mobile networks if their phone isn't able to make Triple Zero calls over 4G.
As part of the 3G shutdown, new legislation means telcos must block devices that can't make Triple Zero calls over 4G from their networks. This is to ensure that all phones operating in Australia can make emergency calls, which has been a matter of concern in the lead-up to the shutdown.
These new rules could also end up adversely impacting international visitors. International models are less likely to be properly configured to make Triple Zero calls over 4G in Australia, and as such, may simply not work on arrival.
Telstra and Optus both confirmed to WhistleOut that they are blocking all non-compliant phones from international visitors. This is regardless of whether they roam on to the Telstra or Optus network via their overseas mobile provider or buy a local SIM (or travel eSIM) on one of the networks.
Both providers are using TAC-based blocking. A TAC is part of a phone's unique identifier that corresponds to the manufacturer and model. All iPhone 11 models sold in the United States have the same TAC, for example. If Telstra or Optus have chosen to block US iPhone 11 variants, this applies to every single device.
In effect, this means Telstra and Optus have a list of devices that can no longer operate on their networks. Any phone that has the same TAC won't operate.
"International roamers with a device that has been identified as non-compatible with our network will be blocked from connecting to our network," said a Telstra spokesperson. "This will be instantaneous from the moment the traveller first turns on their phone."
"Optus prioritises the safety of all customers," said an Optus spokesperson. "As a result, international visitors who enter the country with phones that are non-compliant and cannot connect to Triple Zero will be blocked."
Vodafone is the only telco currently making use of a clause in the new legislation that allows foreign travellers with a non-compliant phone to keep using Australian mobile networks. The exception allows visitors to use their phone for up to 90 days, provided the telco informs the user they won't be able to make emergency calls.
This is because Vodafone is using IMEI-based blocking to prevent non-compliant devices from accessing its network. An IMEI is a unique number associated with an individual phone. No two phones share the same IMEI. Instead of blocking every iPhone 11 from the United States, for example, Vodafone is only blocking individual models it has detected.
WhistleOut understands that TAC-based blocking could have been a more appealing option for Telstra and Optus due to the number of customers on the networks, and the short time frame in which they had to implement the block for local users. There are over 24 million customers on the Telstra network, over 10 million on the Optus network, and over five million on the Vodafone network.
Phones from overseas are key culprits when it comes to devices that "should" work after the 3G shutdown but don't. This is because they often support different frequencies than models sold in Australia.
For example, iPhone 11 models (and older) sold in the United States don't support Band 28 on 4G networks, which is required to make VoLTE calls. This isn't an issue with iPhone 12 models are newer.
Overseas devices blocked from Australian mobile networks can still use WiFi when down under.
The problem should reduce over time, as more and more people around the world upgrade to newer models. In the short term though, travellers visiting Australia may need to turn to a Vodafone SIM.
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Alex Choros