The PSTN Shutdown: What It Means for Your Business Landlines
Australia's copper PSTN network is being switched off. Here's what it means for your business landlines and how to move to VoIP cleanly.
If you still run your business phones over a copper landline, you have probably heard the term "PSTN shutdown" and wondered what it actually means for you. The short version: the old copper phone network is being switched off, and any business relying on traditional landlines, ISDN or older PBX hardware will eventually need to move to internet-based calling. The good news is there is no need to panic, and for most businesses the switch ends up cheaper and easier than the system they leave behind. Here is what is really happening, on what timeline, and what to do about it.
What "the PSTN shutdown" actually means
PSTN stands for Public Switched Telephone Network, the copper-based system that has carried phone calls in Australia for decades. As the NBN rolls out, that copper is being retired and voice services move onto the internet instead. The important thing to understand is that this is not one national switch-off date. Australia is retiring the copper network rolling, premises by premises, as the NBN becomes available in each area. Each premises typically gets around 18 months' notice before its copper services stop. So your neighbour's deadline and yours may be years apart.
That is different from the UK, which has a single 2027 cutover. Here, it is gradual, and it depends on your address.
Which businesses need to act
You are affected if your phones depend on any of the following:
Standard copper landlines or ISDN lines
for voice. These are the services being retired as the copper goes.
Telstra DOT (Digital Office Technology)
, which is being retired on 30 August 2027.
Telstra Calling for Office 365
, which is being withdrawn (stop-sell 30 August 2026, full withdrawal 30 November 2026).
An ageing on-premise PBX
. As an example, NEC has ceased manufacturing its on-premise PBX/UC line. For Australia, hardware shipping and core technical support ended on 31 March 2026; software and licence support runs to 31 March 2030. Hardware that can no longer be supplied or repaired eventually becomes a risk of its own.
If none of that sounds like you and you are already on a hosted or cloud phone system, you have likely already made the move and can relax.
What you move to instead
Replacing copper voice means moving calls onto the internet. There is no single "right" answer, and that is exactly why it pays to look at your options honestly rather than be sold one product. The common paths are:
Keep your existing phone system, replace the lines.
If your PBX is still healthy, SIP trunks can directly replace ISDN and PSTN lines and keep your current numbers and handsets working.
Move to a modern phone platform.
A 3CX system (hosted or on-premise, with free calls between offices and branches), a hosted PBX, or Microsoft Teams Direct Routing if your team already lives in Teams.
Migrate off legacy hardware.
If you are on an old NEC or Cisco platform, there is a clear path off it onto something supported.
Whichever route you take, internet-based calling usually gives you things copper never could: video, call reporting, IVR and smarter routing on your 1300 and 1800 numbers, and the ability to take your number anywhere.
Don't forget the connection underneath
Internet calling is only as good as the line carrying it. As you plan the move, it is worth checking your business internet at the same time, whether that is business NBN, gigabit fibre or 5G fixed wireless, so voice and data are sorted together rather than in two separate scrambles.
How SIP Connect helps
SIP Connect is a local north-east Melbourne business telco based in Greensborough, with real people you can actually talk to, not an offshore call centre. We are vendor-neutral, so we recommend the platform that fits your business, whether that is 3CX, Microsoft Teams or a hosted PBX, rather than pushing one tied product. Most new phone systems are installed in days, not weeks, and our bill reviews have identified savings of up to 65%.
Frequently asked questions
Do I have to switch before a single national deadline?
No. The copper network is being retired gradually, premises by premises, as the NBN becomes available, with around 18 months' notice for each address. Specific services like Telstra DOT do have firm dates, but there is no single national switch-off day.
Will I lose my existing phone number?
In almost all cases, no. Your numbers can be moved across to internet-based calling, so customers keep dialling the same number they always have.
Is moving off copper expensive?
For most businesses it lowers ongoing costs. The aim is to make the change pay for itself, not cost you more.
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