PSTN Shutdown Australia: What Your Business Needs to Do (2026)

Australia's PSTN (Public Switched Telephone Network) copper phone infrastructure has been fully decommissioned as part of the NBN rollout, completed in 2025. This guide covers exactly what that means for your business: what the shutdown actually involved, what happened to your existing phone lines, which devices are most at risk, and what action you need to take now. Unlike generic summaries, this guide addresses the silent migration that already happened to most Australian businesses without their knowledge, the ISDN shutdown that is more urgent for businesses with multiple lines, and the specific devices (fire panels, lift phones, medical alarms) that need dedicated solutions.

What Was the PSTN? Plain English Explanation

The PSTN (Public Switched Telephone Network) was the copper-wire telephone network that powered every landline phone in Australia since the late 1800s. When you picked up a phone and heard a dial tone, that tone was generated by the telephone exchange and delivered to your handset over a pair of copper wires running through the ground from the exchange to your building. The network was circuit-switched, meaning a dedicated copper path was physically established between two callers for the duration of every call.PSTN had some notable characteristics that most businesses never thought about because they just worked. The copper wires carried enough low-voltage current from the telephone exchange to power the phone itself, which is why traditional landlines still worked during power outages. Call quality was extremely consistent because the circuit was dedicated and not shared with internet traffic. Fax machines, EFTPOS terminals, monitored alarm systems, fire panels, and lift emergency phones all relied on this infrastructure in ways that have now become a serious migration challenge.The network was owned and operated by Telstra as a regulated monopoly infrastructure provider. When the Australian Government committed to the NBN, it was always clear that the NBN rollout would eventually replace and retire the copper network. NBN Co and Telstra signed a definitive agreement in 2014 that included a multi-year timetable for Telstra to decommission its copper as NBN reached each area. That decommission is now complete.

The PSTN Shutdown Timeline: What Happened and When

Understanding the timeline helps clarify why some businesses are still confused about their current status. The shutdown was not a single event. It was a rolling, area-by-area decommission that followed the NBN rollout map across more than a decade.

The key milestones:

2009 to 2013: NBN Co established, pilot rollouts begin in selected areas. First copper decommissions in early NBN fixed-line areas (FTTP pilot zones). Businesses and households in those areas received 18-month notices before copper was switched off.2014 to 2020: The multi-technology mix (MTM) approach was adopted, mixing FTTP, FTTN (Fibre to the Node), FTTB (Fibre to the Building), FTTC (Fibre to the Curb), and HFC (hybrid fibre coaxial). FTTN and FTTB technologies kept the copper for the final segment from node to premises. Copper decommissions proceeded only in full FTTP and HFC areas during this period.2019 to 2023: NBN Co declared its network 'built and fully operational' across the national footprint. Telstra began accelerated copper decommission in areas with full NBN coverage. The 18-month decommission notices were issued in rolling waves.2024 to 2025: Final copper decommissions completed. All PSTN copper lines that were not already converted to NBN infrastructure were cut over or permanently disconnected. From 2025, new PSTN lines cannot be provisioned anywhere in Australia. Existing copper is no longer maintained and will be progressively removed from the ground.

What 'Switched Off' Actually Means for Your Business

Switched off does not mean all business phones stopped working on a single day. What it means is that the underlying infrastructure has changed and all calls now travel over digital IP (internet) networks rather than dedicated copper circuits. Whether you noticed this change depends on who your carrier is and how your premises was connected.For most businesses on standard NBN connections with ISP-supplied modems, the transition was invisible. The ISP configured an Analog Telephone Adapter (ATA) port on the NBN modem, migrated your existing phone number to a VOIP service running over NBN, and your phone kept ringing. From your perspective, nothing changed. From a technical perspective, everything changed. If your business phone stopped working after an NBN switchover, see Business Phone Stopped Working After NBN: What to Do Right Now for immediate steps to recover your service and number.For businesses on ISDN (Integrated Services Digital Network) lines, which were common for companies needing multiple simultaneous calls, the shutdown is a separate and more urgent process. ISDN was already a digital service running over dedicated copper, but it is also being shut down as part of the copper decommission. ISDN shutdown is covered in its own section below.For businesses with specialised equipment, the situation is more complex. Devices that were engineered to work with PSTN analog signal, such as older fax machines, monitored security systems, fire panels, lift emergency phones, and medical alarms, may have stopped working when their copper connection was decommissioned, or may be running on compatibility layers that are not officially supported long-term.

The NBN Silent Migration: What Your ISP Did Without Telling You

This is the central story of the PSTN shutdown that almost no business has been told clearly. When NBN was connected at your premises, your ISP did not call you to explain that your phone service was about to fundamentally change. They sent a technician, installed or activated the NBN equipment, and quietly moved your phone line to a VOIP service running over NBN. Your number still worked. Your calls still connected. Nothing visibly changed.What actually happened: your phone number was migrated from the PSTN copper network to a VOIP service managed entirely by your ISP. That VOIP service is delivered through the ATA port on your NBN modem. The ATA is what makes the green phone port on the back of your modem work. It converts the digital VOIP signal into the analog signal your old handset understands. Your ISP programs the VOIP credentials directly into the modem firmware. You do not own those credentials. You cannot access them. You cannot take them to another provider.This was done deliberately. ISPs retained call revenue, locked customers into bundled plans, and prevented migration to specialist business VOIP providers. Customers who had been on Telstra copper lines for twenty years woke up on NBN with no landline experience and no idea they had options. The good news: the hard part already happened. Your number survived the PSTN shutdown because your ISP moved it automatically. You are not behind. The infrastructure migration is complete. What you now have the opportunity to do is choose a proper business phone system instead of running on the default ISP setup that was never designed for business use. See our guide on migrating your landline to VOIP in Australia for the full migration walkthrough.

ISDN Shutdown: The More Urgent Migration for Multi-Line Businesses

While standard PSTN lines were transitioned to NBN as part of the household and small business rollout, businesses running ISDN faced a parallel and more urgent shutdown process. ISDN (Integrated Services Digital Network) was a premium digital telephone service that businesses paid significantly more for because it offered multiple simultaneous call channels over a single connection.

The three main ISDN products that were sold in Australia:

ISDN2 (also called Basic Rate Interface or BRI): Two simultaneous call channels. Used by small businesses wanting two phone lines without two separate PSTN connections. Cost roughly $80 to $120 AUD per month from Telstra.ISDN10/20/30 (also called Primary Rate Interface or PRI): 10, 20, or 30 simultaneous channels. Used by medium businesses, call centres, and companies with a PBX system that needed to handle multiple concurrent calls. This connected to a physical PBX box on-site and was how many business phone systems operated for decades.Telstra announced the end-of-life for its ISDN products and began the decommission in parallel with the broader copper shutdown. Businesses on ISDN were not silently migrated. They received decommission notices and were required to actively migrate to a replacement service. The replacement is SIP trunking, which delivers the same multi-channel call capacity over a VOIP/NBN connection. See our explainer on the differences between VOIP and traditional phone services for more context on what changed technically.

What devices and services are affected

Businesses that had ISDN-connected on-premise PBX systems (from vendors like NEC, Panasonic, Avaya, Cisco) typically need to do one of two things: add a SIP trunk adaptor (often called a VoIP gateway) that connects the existing PBX to an NBN-based SIP trunk service, or replace the on-premise PBX entirely with a hosted PBX (cloud PBX) system. See our comparison of hosted PBX versus on-premise PBX in Australia to understand which approach makes sense for your business.

What Is Affected by the PSTN Shutdown

The shutdown affects every service that relied on copper PSTN infrastructure. Some of these are obvious. Others catch businesses completely off guard.

Standard business phone lines

Any standard business phone line (also called a POTS line, Plain Old Telephone Service) has been migrated to NBN. If the migration was handled by your ISP as part of NBN connection, your number still works via the modem ATA. If you had a standalone PSTN line that was not bundled with NBN, it is no longer active. You need to contact your carrier to confirm whether your number was migrated and to what service.

Fax machines

Traditional fax machines communicate using analog tones over a dedicated circuit. They do not work reliably over VOIP because VOIP compression algorithms discard or distort the exact frequencies fax uses for handshaking. Many fax machines plugged into ATA adapters appear to send faxes but transmissions fail silently at the receiving end. If your business relies on fax (particularly in legal, medical, or government contexts), you need either an online fax service (T.38 over IP, which is specifically designed for digital fax transmission) or a dedicated fax service provider. Standard ISP ATA ports are not a reliable fax solution.

EFTPOS terminals

Older EFTPOS terminals that used PSTN dial-up connections to process transactions have already been replaced by IP-connected terminals at most businesses. If your EFTPOS terminal uses a phone line to process payments, contact your bank or payment terminal provider immediately. This is a transaction security issue, not just a communications issue.

Fire panels and monitored alarms

This is the highest-risk category. Fire alarm panels in commercial buildings were typically configured to dial the monitoring station over a dedicated PSTN line when an alarm was triggered. That dedicated line gave the system a level of reliability that VOIP cannot replicate: it worked during power outages (copper carried exchange power), it was not shared with internet traffic, and it could not be disrupted by a failed router or ISP outage.If your fire panel was connected to a PSTN line that has been decommissioned and you have not updated the monitoring configuration, your alarm monitoring may have failed silently. This is a building compliance and insurance issue, not just a technology inconvenience. Contact your fire protection company or monitoring provider urgently. Many monitoring providers have specific VOIP-compatible communicators (often using 4G cellular as the backup path) designed for exactly this situation.

Lift emergency phones

Lift emergency phones (also called lift help phones) in commercial and residential buildings dial a monitoring centre or building manager when pressed. Under Australian Standards (AS 1735.12), lifts must have a working means of calling for help. If the PSTN line connected to the lift phone has been decommissioned, the lift phone may not function. Building owners and strata managers need to verify the status of every lift emergency phone in their building. Solutions include IP-based lift phones, 4G cellular lift phones, and VOIP-over-NBN connections with appropriate backup power.

Medical alarms and personal emergency response systems

Personal medical alarms (worn by elderly or at-risk individuals) that dial an emergency centre over PSTN are affected. If the alarm device was designed for PSTN and is now plugged into an ATA adapter, it may appear to function but fail in actual emergencies due to VOIP latency, compression artefacts, or network congestion at the moment of the call. Alarm providers have had years of notice about the shutdown and most have issued updated devices or migration programs. Check directly with the alarm provider to confirm the device is compatible with NBN VOIP and what the recommended configuration is.

Monitored security systems

Security alarm systems that reported to a monitoring centre via PSTN need a confirmed migration path. Many security monitoring companies have already moved customers to IP reporting (over broadband) or 4G cellular backup communicators. If you are unsure whether your security system is still reporting correctly, contact your monitoring company and request a comms path verification. Do not assume it is working.

What You Do NOT Need to Do

Before getting into action steps, it is worth being clear about what has already been handled for you, so you are not doing unnecessary work.If your business is on NBN and your phone plugs into the green ATA port on your modem, your number was already migrated to VOIP by your ISP. You do not need to 'migrate to VOIP'. You are already on VOIP. You do not need to port your number to keep it working. Your ISP already handles the number on your behalf. You do not need to worry about the PSTN decommission itself. That process is complete and your service survived it.What you are currently missing is not VOIP. You are missing a proper business phone system. The ISP ATA gives you one thing: a single phone line that rings. It does not give you multiple simultaneous lines, call queuing, auto-attendant, voicemail to email, call recording, ring groups, after-hours routing, or any of the other features that define a business phone system. That is the upgrade conversation, not the migration conversation.

What You SHOULD Do: Upgrade From ISP Default to a Business VOIP System

The PSTN shutdown is now background context. The real decision for Australian businesses in 2026 is whether to stay on the basic ISP-managed VOIP service or upgrade to a proper business phone system. Here is the case for upgrading.The ISP ATA service was designed to replicate what you had on copper, not to improve it. It gives you a dial tone and a phone number. It does not give you the features your business actually needs. Every month your business runs on the ISP default is a month of:Lost leads from engaged tones when two customers call simultaneously. No call queuing means the second caller hears busy and hangs up. That customer calls a competitor. A business losing even one lead per month from this is likely paying more in lost revenue than a full business VOIP plan costs.Missed calls with no fallback. No after-hours voicemail, no mobile divert, no IVR to set expectations. Customers calling outside business hours get nothing. No message, no callback option, no acknowledgement that you received their attempt.No professionalism layer. Large clients and professional services customers notice whether a business has a real phone system. An engaged tone or a basic voicemail greeting is a first impression you cannot control on the ISP default.A business VOIP system from a specialist provider changes all of this. Multiple simultaneous lines on your existing number. Ring groups so calls route to available staff. Auto-attendant for after-hours and overflow. Voicemail to email so messages are never missed. Call recording for compliance and training. The cost is typically $30 to $60 AUD per user per month, all included. See our full guide to choosing a business phone system in Australia for a breakdown of what is available.

How to Switch: The Practical Steps

Step 1: Confirm your current setup. Check whether your phone plugs into the green ATA port on your modem (ISP-managed VOIP) or connects via Ethernet to a separate VOIP adapter or IP desk phone (you may already be on a VOIP service). If you are unsure, call your ISP and ask whether your phone line is 'NBN VOIP via modem ATA' or a 'standalone VOIP/SIP service'.Step 2: Choose a business VOIP provider. Look for an Australian provider that offers hosted PBX (cloud PBX) with local support, clear pricing in AUD, and experience with NBN connections. Providers that specialise in SMB business communications will ask about your actual call patterns and team size before recommending anything. Be wary of providers that immediately quote a plan without asking how your business operates.Step 3: Port your number. Your existing business number can be transferred (ported) to your new provider. This is a regulatory right under ACMA number portability rules. The porting process takes 5 to 10 business days. Your ISP will release the number when instructed. Your new provider manages the porting process on your behalf. See our full guide to number porting in Australia for the complete porting process and what can go wrong.Step 4: Set up your phone system. Your new provider will configure a hosted PBX with your preferred call routing: ring groups, after-hours voicemail, auto-attendant, and any other features you need. This typically takes a few days and your provider's team handles the configuration.Step 5: Deploy handsets. Once your service is configured, you can add IP desk phones (SIP phones) or softphone apps on computers and mobiles. See our guide to setting up NBN VOIP for your business for the specific setup steps.

NBN Battery Backup: Your Phone Dies When Power Dies

One of the most significant practical differences between the old PSTN and modern NBN VOIP is what happens during a power outage. This is something most businesses discover at the worst possible moment.Traditional PSTN copper phones worked during power outages because the telephone exchange supplied a small amount of power down the copper wire to the phone. As long as the exchange had backup power (which exchanges did), your landline kept working. This was why landlines were traditionally recommended as the backup communication method during emergencies.NBN VOIP phones do not work during power outages. The NBN connection device (NTD/NTU), your router, and your modem all require mains power. When power fails, the entire VOIP chain fails with it. Your business phone stops working. Callers get no response.NBN Co required ISPs to offer battery backup units (also called UPS or backup power supplies) for the NBN connection device at the time of installation. However, many ISPs provided these batteries at additional cost, many customers declined them to save money, and the batteries that were installed have a limited lifespan of 2 to 4 hours under load. If you accepted a battery backup at NBN installation, verify whether it is still functional. Most batteries supplied during the 2012 to 2018 NBN rollout period have already degraded significantly. A well-configured business VOIP system can mitigate power outage risk through call divert rules: if the main office number is unreachable, calls automatically forward to a mobile. Set this up with your VOIP provider as part of the initial configuration. It takes minutes and removes the single biggest resilience gap in NBN-based phone systems.

Special Cases: Fire Panels, Lift Phones, and Medical Alarms

These devices need individual attention because the standard ISP VOIP migration does not solve their requirements and the consequences of failure are serious.

Fire panels

Contact your fire protection company or your building manager. Do not attempt to connect a fire panel communicator to an ATA adapter or standard VOIP service without specific guidance from the manufacturer and your monitoring company. The only reliable solutions are: dedicated IP fire panel communicators (using your broadband connection), 4G cellular communicators (entirely independent of NBN), or dual-path communicators that use IP primary and 4G backup. Your local fire protection engineer can assess which is appropriate for your building type and provide a compliant installation.

Lift emergency phones

Contact the lift maintenance company responsible for your building's lifts. In most commercial buildings this is managed by the building owner or strata corporation. The lift contractor will assess the current emergency phone connection and provide a compliant replacement. Solutions commonly used include 4G GSM lift phones (no NBN connection required), IP-based lift phones over building LAN, and dedicated VOIP lines with UPS backup. Do not allow NBN decommission to proceed without confirming the lift emergency phone is on a working replacement path.

Medical alarms

Contact the alarm provider directly. Most major medical alarm providers (such as MePACS, Tunstall, Alert 1) issued NBN migration notices to customers and provided updated devices during the rollout period. If a device has not been updated and is being used by a vulnerable person, this is urgent. The provider can test the device over the current connection and confirm whether it is functioning correctly. If the device is not NBN-compatible, the provider will supply a replacement unit.

What Most Businesses Get Wrong About the PSTN Shutdown

Mistake 1: Assuming 'nothing changed' means everything is fine. The most common error is that business phone lines kept working through the NBN transition, so businesses assumed their setup was adequate. In reality, the setup they ended up on (ISP ATA, single line, no business features) is the worst possible outcome. It is technically functional but commercially limiting. Their calls work but their business phones do not.Mistake 2: Treating the PSTN shutdown as a crisis rather than a decision point. The shutdown is complete. Panic is not useful. The productive framing is: the industry just forced every Australian business off copper, which means every Australian business now has a clean slate to choose the phone system they actually want. That is an opportunity, not a crisis.Mistake 3: Ignoring specialised devices. Fire panels, lift phones, and monitored alarms are often managed by building owners or facilities teams who assume someone else is handling the PSTN migration. Nobody is handling it automatically for these devices. If your building has any of these systems and you have not specifically verified they have been migrated, verify them now. The NBN transition does not automatically resolve these connections.Mistake 4: Porting a number before having a destination. Some businesses begin the number porting process before their new VOIP service is configured and ready to receive calls. If a port completes and the destination service is not ready, calls to that number go nowhere. Always have your new VOIP service fully set up and tested on a temporary number before initiating a port of your main business number.

Your Next Steps

Work through this checklist in order. Not every item will apply to every business, but each one is worth checking.1. Check how your current business phone connects. Is it plugged into a green ATA port on your modem? Or does it connect via Ethernet to a separate VOIP device? This tells you whether you are on an ISP-managed service or a standalone VOIP service.2. Check whether your number is still active. Dial the number from a mobile to confirm it rings. If it does not ring, contact your ISP immediately to confirm migration status.3. If you had ISDN, confirm migration status. Contact Telstra or your ISDN carrier to verify whether your ISDN service has been formally migrated or is still on a decommission timeline.4. Audit specialised devices. Check fire panels, lift phones, security systems, and medical alarms. Contact the relevant service provider for each to confirm the device is on a working NBN-compatible connection.5. Check your NBN battery backup. If you received a battery backup unit at NBN installation, test it or have it tested. Most units over 4 years old have degraded significantly.6. Evaluate the business case for upgrading from ISP ATA to a proper business VOIP system. Use our VoIP Cost Calculator to estimate what a business VOIP plan would cost your team and compare it against the features you are currently missing.7. If you decide to upgrade, get a recommendation that is specific to your business size and call patterns before committing to any provider or plan. The wrong setup is common and easy to avoid with the right upfront guidance. Start at our Get a Recommendation page.

The PSTN shutdown means millions of Australian business numbers will need to be ported to VoIP services. Our Number Porting Checker confirms whether your current number can be ported and what documentation you will need to have ready.

The PSTN shutdown requires a complete migration off copper voice services — and the planning timeline is longer than most businesses expect. Our Phone System Switch Planner generates a migration timeline and checklist specific to your business size and current setup.

Is the PSTN shutdown in Australia complete?

Yes. Australia's PSTN copper network was fully decommissioned as part of the NBN rollout, with the final decommissions completing in 2025. No new PSTN copper lines can be provisioned. All existing telephone services in Australia now run over NBN or mobile network infrastructure.

My business phone still works. Does that mean I don't need to do anything?

Your phone working means your ISP successfully migrated your number to VOIP as part of the NBN transition. But 'working' in this context means 'makes and receives calls on a single line'. It does not mean you have a business phone system. You are likely missing call queuing, auto-attendant, voicemail to email, multiple simultaneous lines, and after-hours routing. Those features require a proper business VOIP service, not the ISP default.

What happened to my old Telstra landline number?

If your premises was connected to NBN and you had a Telstra landline, Telstra migrated your number to VOIP as part of the NBN process. Your number should still be active on a Telstra VOIP service. If it is not, contact Telstra directly and quote your address and number to confirm migration status. Under ACMA number portability rules, you can port that number to any VOIP provider you choose.

Can I still use my old analog phone handset?

Yes, if it is plugged into an ATA adapter (either the green port on your NBN modem or a standalone ATA device). Analog handsets do not connect directly to VOIP services. They need an ATA to convert the analog signal. If you want to use a modern IP desk phone like a Yealink, you connect it via Ethernet directly to your network, and it connects to your VOIP service over IP, not through the green port.

Does the PSTN shutdown affect fax machines?

Yes. Traditional fax over standard VOIP is unreliable because VOIP compression interferes with fax tones. Many businesses believe their fax is working because the machine reports a successful send, but the receiving end gets a corrupt or empty document. If your business relies on fax, you need either a T.38 fax-over-IP service (which uses a protocol specifically designed for digital fax) or an online fax provider. Your ISP's standard ATA service is not a reliable fax solution.

What about fire panels and monitored alarms after the PSTN shutdown?

Fire panels, lift phones, and monitored alarms that relied on PSTN connections need individual migration paths. Standard VOIP via an ISP ATA is not appropriate for life safety systems because VOIP lacks the reliability guarantees those systems require. The recommended solutions are 4G cellular communicators (which are independent of NBN and broadband), IP communicators specifically certified for fire or security monitoring, or dual-path systems. Contact your fire protection company, security monitoring provider, or lift maintenance company to confirm compliant replacement paths for each device.

Will my phone work during a power outage on NBN VOIP?

No. NBN VOIP phones require your NBN connection device, router, and modem to be powered. During a power outage, all of these fail and your business phone stops working. Traditional PSTN copper phones worked during outages because the exchange supplied power down the line. NBN does not do this. If you need phone availability during outages, you need UPS backup for your network equipment, a mobile fallback (call divert to mobile when VOIP is down), or a 4G-based solution that operates independently of NBN.

Can I keep my existing business phone number when switching to a new VOIP provider?

Yes. Under ACMA number portability rules, you have the right to port your geographic (02, 03, 07, 08) business number to any VOIP provider in Australia. The porting process takes 5 to 10 business days. Your new provider manages the porting process on your behalf. During the port, your existing service remains active so you do not lose calls in transit. See our detailed guide on number porting in Australia for the full process.

What is ISDN and is the ISDN shutdown different from the PSTN shutdown?

ISDN (Integrated Services Digital Network) was a premium digital phone service that provided multiple simultaneous call channels over a single copper connection. ISDN2 provided two channels; ISDN10/20/30 provided 10, 20, or 30 channels. It was widely used by businesses that needed a multi-line phone system connected to an on-premise PBX. ISDN was shut down by Telstra as a separate product line-of-business decommission, running parallel to the broader PSTN copper shutdown. Unlike the silent PSTN migration, ISDN customers received formal decommission notices and had to actively migrate to SIP trunking. If your business had ISDN and you have not yet migrated, contact your telecommunications provider immediately.

Related reading:

• migrating from landline to VoIP
• ISDN to VoIP migration
• VoIP vs traditional phones