The short answer
What a VoIP home phone actually is
When the old copper phone network was switched off for the NBN, the home phone did not disappear, it quietly changed into something different. Your landline is now a Voice over Internet Protocol (VoIP) service: a voice app that turns your speech into data packets and sends them over the same broadband connection that carries your Netflix and your work calls. Plug the handset into your modem instead of a wall socket, keep the same number, dial the same way. For everyday calls it works fine, often with clearer audio. But one thing changed underneath that most people never notice until the worst moment: the old copper line carried its own power down the wire, so it kept working in a blackout. VoIP needs both mains power and a live internet connection, so the moment the power goes out or the NBN drops, your home phone goes silent. This page explains what VoIP actually is, why that reliability shift matters more than any call pack, and what to do about the things that used to just work on a landline.
Here is the core takeaway in one line: a VoIP home phone is a voice app riding your broadband, so unlike the old copper landline that powered itself, it goes dead in a blackout or an NBN outage, which means anything safety-critical on the home phone now needs its own backup. That single fact is the reason the switch to VoIP matters far more than which call pack you pick. The calls themselves are cheap and easy to compare. The thing people miss is that the device they trusted to work when everything else failed, in a storm, a power cut, a medical emergency, no longer works the same way.
Reframe the assumption: the home phone did not stay the same and just move onto the NBN. It became a different kind of device. The old line was self-powered and independent; VoIP is a feature of your internet service. Once you see it that way, every "why doesn't this work anymore" question, from the medical alarm to the lift phone, answers itself.
The blind spot
Why most VoIP guides miss the point that matters
Most "NBN home phone" articles do one of three unhelpful things, and each one leaves you exposed in the moment a phone is supposed to save you.
First, they treat VoIP as just a cheaper landline. They line up call packs, compare PAYG against unlimited and declare a winner, as if the only question were price. That is the easy half. They skip the half that can actually hurt you: what happens when the power or the internet goes down.
Second, they bury the reliability change in a footnote. You will often see one line near the bottom saying VoIP "needs power and internet" and move straight on. But that is not a footnote, it is the headline. The whole reason the copper landline was special is that it kept working when nothing else did, and VoIP simply does not, so a passing mention does not do the change justice.
Third, they ignore the devices that quietly relied on the old line. Medical alarms, back-to-base security systems, lift emergency phones and even some EFTPOS machines were wired for copper. A guide that only talks about handsets and call rates never warns you that the alarm on your wall may have stopped phoning home the day the copper was switched off.
How VoIP works, piece by piece
Expert analysis: what really happens when you make a VoIP call
Your voice becomes data packets on the same pipe as everything else
When you speak into a VoIP handset, the device samples your voice and breaks it into small packets of data, like a stream of tiny electronic envelopes, then sends them over your broadband connection to the other phone, where they are reassembled into sound. The old copper service did something physically different: it sent a continuous analogue signal down a dedicated wire from your home to the exchange. The practical upshot is that your home phone is no longer a separate utility. It shares the pipe with your streaming, your video calls and your downloads, and it depends on the same modem being switched on and online.
The copper switch-off is why this happened to everyone, not by choice
This was not a feature you opted into. As the NBN rolled out, NBN Co disconnected the old copper phone network in each area, generally about 18 months after the NBN became available there. Once the copper was switched off, a traditional landline was simply no longer possible, so a home phone had to move to VoIP over the broadband connection. That is why millions of Australians ended up with a VoIP phone without ever deciding to, and why the reliability trade-off caught so many people by surprise.
Self-powered line versus a phone that depends on your power
The detail that changed everything is power. The copper network carried a small electrical current from the telephone exchange, which had its own backup batteries and generators. That is why a basic corded landline kept working in a blackout: the line powered the phone. A VoIP setup draws its power from your home. Your modem runs off a power point, and a power cut takes it down instantly, taking your home phone with it. An NBN outage does the same thing even when your power is fine. So a VoIP phone has two single points of failure the old line never had: your mains power and your internet connection.
Your number ports, but your emergency location works differently
The good news is continuity: in almost all cases you keep your existing number, which your new provider ports across from the old service. The thing to watch is emergency calling. You can still dial triple zero (000) while the power and internet are up, but a VoIP service does not always pass your fixed physical address to the emergency operator the way the old line reliably did, and it will not connect at all during an outage. For the Telecommunications Industry Ombudsman (the TIO) and the regulator, this is exactly why households with a critical reliance on the phone are urged to keep a mobile as a backup.
Interactive explainer
Will my VoIP phone work when I need it?
Tick what you rely on your home phone for, and this flags the real risks of a VoIP line and the backup you should put in place. It works from what fails when the power or internet drops, the thing that actually decides whether VoIP is safe enough for you.
Check your VoIP reliability risk
Indicative guidance only. Always confirm life-safety devices with the device provider before the copper is switched off.
What do you rely on the home phone for?
Your reliability verdict
This tool flags risks only; it does not check your specific device. A battery backup unit (a UPS) typically keeps a modem running for a limited window, often a few hours, before it too runs flat, so it buys time rather than removing the risk. For emergencies, a charged mobile is the most reliable fallback.
Assumptions: a standard VoIP home phone over the NBN with no battery backup, drawing power from your home. Sources: NBN Co guidance on the copper switch-off, ACMA, and Telecommunications Industry Ombudsman (TIO) advice for households with a critical phone reliance.
| What you rely on | Old copper landline | NBN VoIP home phone |
|---|---|---|
| Powers the handset | From the phone line itself, central exchange battery | From your home power point and modem |
| Works in a blackout | Yes, the line carries its own power | No, unless you add a battery backup unit |
| Works in an NBN outage | Separate network, usually unaffected | No, the call rides your broadband |
| Carries your own number | Yes | Yes, ported across in most cases |
| Medical alarm / back-to-base alarm | Generally compatible out of the box | Must be checked and often re-registered |
| Call audio quality | Standard analogue | Often clearer, true HD voice on some plans |
What this looks like in real homes
How the VoIP switch catches Australians out
The mechanics above are not theory. They are exactly how households get caught when the home phone they trusted quietly stops being self-sufficient:
The medical alarm that went silent
An older Australian keeps a monitored pendant alarm wired to the home phone. The copper is switched off, the line moves to VoIP, and nobody tells the alarm provider. The alarm still looks fine on the wall, but it can no longer reach the monitoring centre reliably, and in a blackout it cannot call at all. The fix was a phone call to the alarm provider before the switch, not after.
The storm that knocked out the only phone
A regional household loses mains power in a storm, exactly when they need to call for help. The old corded landline would have worked; the VoIP phone is dead because the modem has no power. With no charged mobile and no battery backup, the household has no way to call out until the power returns.
The security alarm that stopped phoning home
A small business keeps a back-to-base alarm that dialled a monitoring centre over the copper line. After the NBN switch the alarm cannot connect the same way, so a break-in no longer triggers a call. The alarm needed re-registering or an upgrade to a path that does not depend on the old line.
The number nearly lost in the switch
A family cancels the old service themselves to save a fortnight of line rental before the new VoIP plan starts. Cancelling releases the long-held home number, and getting it back becomes a battle. Letting the new provider manage the port, and keeping the old service live until it completes, would have kept the number safe.
The insider insight
The home phone stopped being a safety device the day it became VoIP
Here is the part most VoIP guides never say out loud. For decades the home phone was quietly the most reliable thing in the house, the one device you could count on in a blackout, a flood or a medical emergency, because the copper line powered itself from an exchange with its own batteries. That reliability was invisible precisely because it never failed. The switch to VoIP did not just move the phone onto the internet, it removed that hidden guarantee. A VoIP home phone is a convenience and a cost saving, but it is no longer the thing you fall back on when everything else is down, because it falls down with everything else.
The non-obvious truth: the VoIP question is not "which call pack is cheapest", it is "what am I still trusting this phone to do that it can no longer guarantee". If the answer is just ordinary calls, VoIP is fine and a mobile is your blackout backup. If the answer includes a medical alarm, a monitored security system or a need to call for help when the power is out, the home phone is no longer enough on its own, and you need a deliberate backup: a battery unit on the modem, a re-registered device, or a charged mobile that is always the real emergency line.
The practical consequence: judge a VoIP home phone first on what fails when the power or internet drops, and only second on what each call costs. The call costs are the easy part; the reliability is the part that actually protects you.
Grounded in the analysis
What you should actually do about your VoIP home phone
Specific moves that follow from how VoIP really works, not generic advice.
Register and check every critical device
Before the copper is switched off, tell your medical alarm, security alarm and any lift or monitored device provider that you are moving to VoIP on the NBN, so they can confirm compatibility or re-register the device. Use the checker above to list what needs attention.
Set up a deliberate blackout backup
Decide your fallback for when the power or internet is out. A charged mobile is the most reliable emergency line for triple zero. A battery backup unit on your modem buys a limited window of VoIP calling, but it runs flat, so it supplements a mobile rather than replacing it.
Port your number, do not cancel it
Let your new provider port your existing home number across, and keep the old service active until the port confirms. Never cancel the old line yourself first, because that can release a long-held number and make it hard to recover.
Weighing up whether a VoIP line is even worth it against the call costs? See how a home phone stacks up in a VoIP and bundle plan, or read our NBN plans guide to choose the broadband it rides on.
Current figures, last updated 2026-06-16
Indicative Australian VoIP home phone facts for 2026. Sources: NBN Co guidance on the copper switch-off, the Australian Communications and Media Authority (ACMA), and the Telecommunications Industry Ombudsman (TIO). Behaviour varies by modem, provider and connection type.
The bottom line
Why the reliability change matters more than the call rates
A VoIP home phone is a perfectly good way to keep a landline number on the NBN, and for everyday calls it is cheap, clear and easy. But it is a different device from the copper line it replaced: a voice app riding your broadband rather than a self-powered wire, which means it falls silent in a blackout or an NBN outage instead of carrying you through one. Treat that as the headline, not the footnote. Register and check anything safety-critical, set a deliberate backup with a charged mobile as your real emergency line, port your number rather than cancelling it, and only then worry about which call pack you want. With the copper gone for good, the home phone you can count on in a crisis is the one you have planned a backup for.
Common questions
A Selectra expert answers your VoIP home phone questions
A VoIP (Voice over Internet Protocol) home phone is a landline that runs over your internet connection instead of a copper wire. It turns your voice into digital data packets and sends them over your NBN or other broadband service, then turns them back into sound at the other end. To you it looks identical: you plug a normal handset into your modem, keep your old number and dial the same way. The difference is underneath. The old landline was a separate physical line that carried its own power, so it worked on its own. A VoIP phone is really an app riding your broadband, which is why it depends on your modem, your power and your internet all being up.
No, not on its own. This is the single most important thing to understand about the switch to VoIP. The old copper landline drew power down the phone line from the exchange, so it kept working when your house lost power. A VoIP phone needs your modem powered on and your internet connection live, and both of those die the instant mains power goes out. If you need to make calls during a blackout, your options are a battery backup unit (a UPS) that keeps the modem running for a while, or a charged mobile phone as your fallback. For triple zero (000) in an emergency, a mobile is the most reliable backup.
Not automatically, and this is where people get caught out. Medical alarms, back-to-base security alarms, lift emergency phones and some EFTPOS terminals were built for the old copper line and do not always work over VoIP. Before the copper is switched off at your address, you need to tell your alarm provider you are moving to the NBN so they can check compatibility and re-register or replace the device. NBN Co keeps a register for medical alarm and security users for exactly this reason. Never assume a life-safety device will keep working after the switch, always confirm it with the device provider.
In almost all cases, yes. Your number is portable, so when you move to a VoIP service your provider arranges to carry it across from the old line. Porting is usually free or a small fee and takes a few days. One tip: do not cancel your old service yourself before the port completes, because cancelling can release the number and make it harder to keep. Let the new provider manage the port, and keep the old service active until they confirm the number has moved.
You can still call 000 from a VoIP home phone while the power and internet are up, but two things changed. First, the call will not get through during a blackout or NBN outage, when you might need it most, which is why a charged mobile is the recommended emergency backup. Second, a VoIP service does not always pass your physical address to the emergency operator the way the old fixed line did, so be ready to state your location clearly. For anyone who relies on the home phone for emergencies, treat a mobile as the primary safety net.
That is a genuine choice rather than a default. Because the copper line is gone, keeping a home phone now means adding a VoIP service to your broadband, and many households decide a mobile plan with unlimited calls does the same job more simply. A VoIP line still makes sense if you want a fixed number the whole household shares, prefer a handset for long calls, or call landlines and international numbers a lot. If you do keep one, treat the reliability question first and the call costs second, because the call costs are the easy part to compare.
