Why is Australia’s 3G being shut down – and could it spell chaos?

It’s the end of an era as Telstra and Optus prepare to shut down 3G – a mobile network that dates back to the early days of the iPhone – at the end of August.

While there are few phones in the market that will be affected, business groups are worried that alarms, CCTV and other products reliant on 3G will be, and that Australian businesses might not realise until it’s too late.

Here’s what you need to know.

What is the 3G shutdown?

Mobile network providers Telstra, Optus and TPG operate – or have until recently operated – three generations of mobile networks: 3G, 4G and 5G.

Related: Shutdown of 3G networks a ‘health and safety issue’ for some regional Australians

Most new mobile phones will connect to 4G or 5G, but fall back to 3G when those networks are unavailable – particularly in regional and remote parts of Australia.

Plus, a lot of non-handset devices – such as ATMs, CCTV, Eftpos, fridges, vending machines, medical alert systems and more – have used the 3G networks to connect to the internet and stay online.

Why is 3G being shut down?

The network operators say they’re shutting down the network, as with 2G, to free up the radio spectrum for 5G networks.

Using the spectrum for 5G – which allows more users at higher speeds – will allow them to keep up with the increasing demand for data on mobile networks, which Telstra says grows by 30% every year.

James Chisholm, the infrastructure department’s deputy secretary in communications, told a parliamentary inquiry that 3G would not be able to withstand the demand for the “greater use of video technology and streaming on devices” and “as technology advances and consumers expect more and more services – on their phones, for example”.

When are the networks shutting down?

TPG, the parent company of Vodafone, has already shut down its 3G network, calling time at the end of 2023.

Optus and Telstra are slated to shut down their networks on 31 August but Telstra has said it will keep small pockets of 3G active until there is equivalent 4G coverage in those areas.

• Sign up for Guardian Australia’s free morning and afternoon email newsletters for your daily news roundup

Will it mean worse mobile coverage?

Probably not. There is concern in regional and remote parts of Australia, but the telcos say they’re planning the same or better 4G coverage by the time 3G is switched off. Provided the devices are 4G-compatible, they say customers shouldn’t even notice.

TPG told the inquiry that it received very low levels of customer complaints after it switched 3G off.

How many handsets currently won’t work on 4G?

A major concern for the shutdown – and the reason Telstra delayed its shutdown from June to August – is that more than 740,000 4G handsets at the start of this year were not compatible to make calls on 4G – they used 3G.

The communications minister, Michelle Rowland, said this week that this number had been reduced to about 100,000.

Telstra said about 33,000 handsets on its network were 3G-only. TPG said it had some 228 3G-only devices – even though it doesn’t operate 3G any more – and another 8,000 or so 4G devices unable to make calls on 4G. Optus did not provide its breakdown figure to the hearing.

People who aren’t sure if their device is affected by the 3G shutdown can text the number 3 to 3498 to check.

What if I can’t afford a new phone?

The telcos say that they’ve been in contact with customers affected by the shutdown with a range of offers for a compatible phone, with thousands of those enduring hardship able to get a phone for free.

What about other devices?

While the focus of the messaging about the shutdown has concerned people’s mobile phones, there are many other devices that connect to the internet via 3G.

Telstra says it has 399,000 internet-of-things devices – such as water meters, electricity meters and more – that are not 4G-capable, as well as 63,000 early-version smartwatches and 45,000 wireless broadband devices or tablets.

Optus says it has about 100,000 devices predominantly used by small and large businesses, including payment terminals, monitoring and telemetry devices.

TPG says it has more than 13,000 non-handset devices on its network that aren’t 4G-compatible.

What will happen with those devices?

The telcos say they’ve been attempting to work with the businesses that supply those products to make sure they’re being replaced or upgraded before the deadline. But business groups and other organisations that have relied on 3G devices have raised concerns that most won’t be aware the switch-off is happening or what devices might be connected.

“A fridge isn’t going to complain,” the Royal Flying Doctor Service’s chief information officer, Ryan Klose, told the parliamentary inquiry. He said the service was spending more than $200,000 replacing devices and relying on Starlink’s low-Earth orbit satellite service as a 3G alternative in regional and remote areas.

Will there be a 3G network outage apocalypse in September?

It could spell chaos. The small business and family enterprise ombudsman, Bruce Billson, told the inquiry the first time many businesses may learn their device connects via 3G is when it stops working.

Further the Australian Chamber of Commerce and Industry’s Jodie Trembath warned the parliamentary inquiry that crucial services, such as warning, alarm and pump systems, might not be switched over before the cut-off.

The department said it had spent the past year engaging with the affected sectors, such as banking, and their peak bodies to amplify the message about the upcoming shutdown. It continued that the Commonwealth Bank, NAB and Westpac have said there are less than 3,000 Eftpos machines left across Australia using 3G and they’re working to replace them all.

The medical alarm industry was also “well advanced” in switching over customers to 4G, the department added.

Can the government force the telcos not to shut down 3G?

The communications minister has the option to consider regulatory intervention in the public interest, including to protect public safety, the department said. And Rowland could also, hypothetically, delay the shutdown, Chisholm said.

A previous minister, Helen Coonan, used the power to delay the shutdown of the CDMA network to transition to 2G.

Chisholm told the inquiry the focus was on ensuring that the transition away from 3G happened when the identified issueshad been adequately addressed.