PSTN Shutdown Australia: What Businesses Need to Check in 2026

This guide explains what Australia's copper landline transition means for a small or medium business, including how to identify its current phone service and decide whether any change is needed. Unlike summaries that treat the old Public Switched Telephone Network (PSTN), the legacy telephone network that carried calls over fixed lines, as if it ended everywhere on one date, it separates the nbn fixed-line transition from Fixed Wireless, Sky Muster, Special Services and private-network exceptions using current Australian guidance. By the end, you will know what to check at your premises, which devices need specialist confirmation, and when keeping, migrating or upgrading the service is the safer choice.

Is Australia's PSTN Actually Shut Down?

The broad transition away from conventional PSTN services is real, but describing Australia's copper network as universally gone is inaccurate. nbn says premises served by its Fixed Wireless and Sky Muster satellite technologies are not disconnected from existing phone services by nbn and can have the option to retain an existing copper landline through their provider. nbn explains which services are switched off and which are not.The phrase “PSTN shutdown” is therefore useful shorthand for a long, area-by-area migration, not a statement that every copper pair or legacy service ceased on one national date. Although 2025 is commonly used as shorthand for the end of the mass transition, businesses should not infer their own service type from that year alone.Use this distinction when assessing a site:

Premises or service type	What may have happened	What to check
nbn fixed-line area	An affected legacy landline may have been replaced by a voice service supplied over the new connection	Ask the phone provider for the service type and account details
nbn Fixed Wireless area	An existing copper landline may have remained available separately from the wireless internet service	Confirm whether the copper service is active, billed and supported
nbn Sky Muster area	An existing copper landline may have remained available separately from the satellite internet service	Confirm the landline status with its provider
Special Service	The service may have followed its own migration and disconnection path	Identify the product, carrier and applicable migration advice
Private or non-nbn network	The arrangement may sit outside nbn's standard disconnection process	Ask the network owner and service provider what infrastructure carries it

This is why an address-level and service-level check is safer than relying on a national shutdown headline.

What Changed When nbn Replaced Legacy Phone Services

A traditional PSTN call used a telephone service delivered through the legacy fixed network. Some simple corded phones could receive line power from the telephone network, which meant they could continue operating through a local power outage when the rest of the voice path remained available.Many replacement services use Voice over Internet Protocol (VoIP), which turns speech into digital traffic, much like an online meeting carries voices over a data connection. The handset can look and behave much as it did before even though the underlying call path has changed.Some customers experienced a provider-managed transition in which the provider configured the replacement voice service and the existing number and handset continued working. That outcome does not establish why the provider chose a particular setup, and it should not be treated as evidence of an attempt to restrict switching.Call quality now depends on more than the handset. The retail voice service, nbn access connection, local cabling, modem or router, network congestion and any Wi-Fi link can affect performance, so assess quality during the site's busy periods and raise recurring faults with the provider.

How to Identify What Phone Service You Have

Start with the physical connection, then confirm what the provider has recorded. The appearance of a handset or wall socket is not enough to identify the service reliably.

1. Check the site's nbn access technology

Use nbn's address checker or ask the internet provider whether the premises uses a fixed-line technology, Fixed Wireless or Sky Muster. This first distinction matters because the copper disconnection rules are not identical across those footprints.

2. Trace the handset cable

Follow the phone cable to its destination:

• If an analogue handset connects to a socket marked PHONE, TEL or something similar on an internet service provider supplied modem or router, the service is commonly provider-managed VoIP.
• If the handset connects through a separate small adapter, that device may be an analogue telephone adapter.
• If the phone connects directly to the data network with an Ethernet cable, it is probably an IP phone, meaning a handset that communicates with the phone platform digitally.
• If it connects to old building phone cabling, trace where that cabling terminates. It may be patched back to a modem, adapter, on-site phone system or a remaining carrier service.

Port colour is not a dependable test. A green socket may be used by some equipment manufacturers, but the label, cabling and provider's records are more useful than colour alone.

3. Ask the provider precise questions

Ask for written answers to these questions:

• What product name and service type carries this number?
• Is it a conventional copper landline, provider-managed VoIP, a standalone hosted phone service or another arrangement?
• Which nbn or non-nbn access technology serves the premises?
• How many simultaneous calls does the service support?
• What happens to incoming calls when the site loses power or internet access?
• Does the service support Triple Zero calls, and what service address is recorded?
• Are any fax, alarm, lift, fire-panel, EFTPOS or medical devices listed on the account?

Do not place a test call to 000. Confirm emergency-calling support and the registered service address with the provider, then maintain a separate emergency communication option for outages.

Why an Old Handset May Still Look Like a Landline

An analogue telephone adapter (ATA) converts digital VoIP signalling into the electrical interface expected by an older handset, like an interpreter between an old telephone plug and a modern phone service. The ATA may be built into the modem or supplied as a separate box.This explains why a business can still hear a familiar dial tone and use the same handset after its underlying service changes. It does not, by itself, reveal the service's call capacity, outage behaviour, number ownership, fax compatibility or available business features.An ATA is not automatically unsuitable for business use. Its suitability depends on what is connected to it, how the provider supports it and whether the overall service meets the business's operational requirements.

Fixed Wireless, Sky Muster and Special Service Exceptions

nbn states that connecting to Fixed Wireless or Sky Muster does not itself alter an existing copper service at the premises. A business in one of these areas may be able to keep its existing copper phone line or choose a VoIP service, subject to what its retail provider offers. The current Fixed Wireless guidance explains this choice, as does the Sky Muster guidance.Do not assume that seeing Fixed Wireless or Sky Muster in an address result proves the copper service remains active. Confirm that it has an active account, dial tone, incoming-call path, fault-support arrangement and current provider.Special Services are business telecommunications products delivered over legacy infrastructure that are handled separately from standard landline and internet services. nbn directs affected organisations to their provider for the product's expected disconnection date and migration path. nbn maintains current Special Services guidance.A privately operated fibre, copper or voice network may also fall outside the standard nbn migration process. Identify the network owner, carrier, service identifier and contractual support path before changing equipment.

What Happens During a Power Outage

Most phone services delivered over nbn depend on powered equipment at the premises. A working voice path may involve nbn equipment, the modem or router, an ATA, a private branch exchange (PBX), which is the system that distributes calls around a business like a reception desk, network switches, cordless-phone bases and handsets.Backing up one component does not guarantee that the whole voice path will remain available. Each required device needs suitable backup power, while an upstream provider or network outage can still interrupt service.nbn's current guidance says it stopped offering new Fibre to the Premises power supply units with battery backup from June 2024, although a phone or internet provider may be able to arrange one. Existing nbn battery units power the nbn connection box, not automatically the router, phone system, cordless base or other equipment. See nbn's battery backup information.A business continuity plan can combine appropriate uninterruptible power supplies, charged mobile phones, provider-level call diversion and an independently tested mobile service. Check whether call diversion happens in the provider's network, because forwarding that relies on powered equipment at the premises may fail with that equipment.The Australian Communications and Media Authority says 000 can be called from fixed and mobile phones and certain VoIP and satellite services. It also warns that most nbn-connected services will not work during a power outage and that VoIP callers may need to state their town and state. ACMA's emergency-calling guidance explains these limitations.

Fax, Alarms, Lifts and Other Legacy Devices

A device producing a dial tone is not proof that every attached machine will communicate correctly. Test each workflow with the organisation responsible for the equipment and retain written confirmation of compatibility where safety, compliance or revenue is involved.

Fax machines

Fax performance over VoIP varies with the provider, ATA, fax machine and codec, the software that compresses call audio like reducing the size of a sound file. Audio compression, packet loss and configuration differences can interfere with fax signalling.T.38, a fax relay method that carries fax data through an IP network rather than treating it as ordinary speech, is one possible approach when supported across the required path. Online fax is another common option. Confirm end-to-end compatibility and test sending and receiving before relying on either approach for a critical workflow.

Fire alarm diallers and monitored security alarms

Contact the fire equipment company or alarm monitoring provider to identify the current communication path, approved replacement options, power requirements and testing procedure. Ask the responsible organisation to perform or witness a communication test after any change.Do not move a safety-critical alarm onto an ordinary ATA or VoIP service without confirmation from the organisation responsible for that system. nbn similarly directs users to the equipment and phone providers for compatibility advice. See nbn's device compatibility guidance.

Lift emergency phones

The lift maintenance company, building owner or strata manager should confirm how each lift phone reaches its monitoring point, what happens during an outage and how the system is tested. The appropriate architecture depends on the lift equipment, monitoring arrangement, building obligations, coverage and backup-power design.Avoid prescribing an ordinary VoIP line, mobile communicator or other technology without that assessment. The lift service company should confirm the supported solution and record successful testing.

Medical alarms and emergency call devices

Contact the device supplier or monitoring provider before changing the phone service. Ask whether the exact device model is supported on the proposed connection, whether it needs a replacement or separate communication path, and how outage operation will be verified.The user should not be asked to infer compatibility from a successful ordinary phone call. The monitoring provider should confirm that an actual alarm signal is received correctly.

EFTPOS and other dial-up equipment

Older payment, health-claim and telemetry devices may use a telephone connection even when staff think of them as separate systems. Contact the bank, payment acquirer or device supplier to identify the connection and supported alternatives before altering the line.

Does a Business Need to Replace Basic ISP-Managed VoIP?

Being on internet service provider managed VoIP does not automatically mean a business needs a different provider or phone system. Keeping the existing service is a reasonable decision when it satisfies the site's requirements and the provider can support the complete setup.Assess it against these needs:

• Enough simultaneous calls for normal and peak periods
• Voicemail that staff can retrieve reliably
• Call forwarding for absence and outages
• Clear after-hours handling
• Mobile answering where staff work away from the premises
• Practical access for multiple users
• Acceptable call quality on the site's nbn connection
• A documented resilience plan
• Responsive fault and account support
• Confirmed treatment of safety-critical devices
• Supported 000 calling with accurate address information

If the answer is satisfactory across the relevant items, leaving the service alone may avoid cost and migration risk. If several gaps affect callers or continuity, compare upgrades against those specific gaps instead of treating the PSTN transition itself as the reason to buy.

When a Business Phone System Upgrade Is Worth Considering

A hosted or cloud PBX is a provider-run call-management system, much like moving the office receptionist and switchboard functions into a managed online service. It can be worth considering when several people answer one business number, callers regularly encounter busy signals, calls need queues or menus, staff work across locations, or after-hours routing is inconsistent.A SIP trunk is a digital connection that supplies calling capacity to a compatible on-site PBX, similar to replacing a bundle of external phone lines with one managed digital link. It may suit a business that has a serviceable PBX and a clear reason to retain it.The upgrade decision should also account for implementation consequences. These include handset replacement, internal cabling, staff training, power backup, internet failover, contract exit costs, number porting and configuration ownership.Australian Consumer Law may protect some small-business purchases depending on the contract value and type of service. Services covered by consumer guarantees need to be supplied with due care and skill and be fit for a disclosed purpose, so document requirements such as call capacity, failover and device compatibility before signing. The ACCC explains consumer guarantees for business purchases, while ACMA explains telco contracts and exit terms.

ISDN Is Historical Migration Context, Not a Universal 2026 Deadline

Integrated Services Digital Network (ISDN) was a digital telephone service that provided multiple call channels over legacy fixed infrastructure, much like carrying several business lines through one connection. Mainstream ISDN migration has already occurred, so it should not be presented as a new nationwide 2026 deadline.A business that encounters an unusual legacy service should identify the exact product, carrier, circuit number and connected PBX before deciding what replaces it. Depending on the existing equipment and operating needs, options can include a SIP trunk, a hosted or cloud PBX, replacement carrier access or another provider-approved architecture.Do not order a generic “ISDN replacement” without auditing every number, call route and attached device. Legacy services can support fax, alarms, door systems or other functions that are not obvious from the monthly bill.

Keeping and Porting Business Phone Numbers

Porting means transferring the right to use a phone number from one provider to another, like moving a business mailing address between service operators without changing the address customers know. ACMA says customers may port eligible local, mobile, 1800, 13 and 1300 numbers, with different industry processes applying to different number types. ACMA outlines the number-porting rules.Keep the existing service active while the gaining provider prepares the request. ACMA warns that only an active service can be ported, so cancelling first can put the number at risk.For an individual local number, ACMA says providers generally complete ports within 8 to 15 days. More complex local-number ports can take up to 30 days, with limited exceptions, but businesses should obtain a provider-specific schedule because account mismatches, number ranges and connected services can alter the process. A mobile number ports much faster: ACMA says mobile ports are usually completed within about 3 hours. See ACMA's porting timeframes.Before authorising a port, record every number and feature on the account, confirm the legal account name, prepare a tested destination and agree on a rollback and escalation plan. A 13, 1300 or 1800 number may have its own routing configuration, so confirm both ownership and destination routing rather than assuming a landline port will move it automatically.Porting is a controlled migration with dependencies, not a guarantee of zero downtime or zero risk. Ask the gaining provider how incoming and outgoing calls will be tested and what support is available on the planned completion day.

What Most Businesses Get Wrong

Mistake 1: Treating the national headline as an address-level answer

“PSTN shutdown” does not reveal whether a particular site uses nbn fixed-line access, Fixed Wireless, Sky Muster, a Special Service or a private network. Check the address technology and service account separately.

Mistake 2: Assuming a working handset proves the whole setup is suitable

A handset can make ordinary calls while fax, alarms, outage forwarding or simultaneous-call capacity remains unverified. Audit the workload and every attached device, not just dial tone.

Mistake 3: Replacing a functioning service without a defined problem

An ISP-managed VoIP service can be adequate for a small business with simple calling needs. Upgrade when documented requirements are not being met, not because a shutdown article implies replacement is compulsory.

Your Next Steps

Work through this checklist before changing or cancelling anything:

• Check the nbn access technology for every business site.
• Trace each handset, fax, alarm, lift phone, fire panel, payment terminal and medical device to its connection point.
• Ask each phone provider to identify the service product and underlying access arrangement in writing.
• Confirm simultaneous-call capacity, voicemail, forwarding, after-hours handling, mobile answering, multi-user access and support.
• Confirm 000 support and the service address without placing a test emergency call.
• Ask each safety-critical equipment or monitoring provider to confirm compatibility and testing requirements.
• Map every powered component in the voice path and test the documented outage plan safely.
• Record all local, mobile, 13, 1300 and 1800 numbers and their routing before requesting a port.
• Review contract exit terms and disclose the required business purpose to a prospective supplier in writing.
• Keep the current service active until an accepted migration or porting plan says it is safe to cancel.

If the diagnosis remains unclear, the site's Get a Recommendation pathway can be used to describe the current setup and requirements before considering an upgrade.

Related reading:

• migrating from landline to VoIP
• ISDN to VoIP migration
• the full number porting guide
• a VoIP cutover checklist
• NBN battery backup for VoIP
• what to do if your business phone stopped working after NBN
• Best Business Phone System for Small Business AU
• VoIP vs Traditional Phone for Australian Business

Is Australia's PSTN copper network completely gone?

No. Most affected legacy fixed voice services in the nbn fixed-line footprint have transitioned or been disconnected, but nbn says premises in Fixed Wireless and Sky Muster areas are not disconnected from existing phone services by nbn and may retain a copper landline through their provider. Special Services and private networks can also follow different arrangements.

My landline still works. Is it still PSTN?

Not necessarily. It may be provider-managed VoIP delivered through a modem or adapter, a retained copper service in an eligible area, or another carrier arrangement. Trace the cable and ask the provider to identify the product and access technology.

Does a PHONE or TEL socket mean I am using VoIP?

An analogue handset connected to a PHONE, TEL or similar socket on a provider-supplied modem is commonly using provider-managed VoIP. Confirm the service type with the provider because labels and port colours do not prove the architecture in every setup.

Can I keep using an old analogue handset?

Often, if the provider supports it through a compatible ATA or modem phone port. Confirm support for caller identification, voicemail, emergency calling and any other required features rather than assuming basic dial tone proves full compatibility.

Will my business phone work during a blackout?

It depends on the service and every powered component in its path. Most nbn-connected phone services will not work without appropriate backup power, and backing up the nbn connection box alone may leave the router, ATA, PBX, network switch or handset unpowered.

Can I call 000 from VoIP?

ACMA says certain VoIP services can call 000, but support should be confirmed with the provider. Most nbn services may be unavailable during a blackout, and VoIP callers should be ready to state their location, so keep an independent emergency communication option where practical.

Will a fax machine work over nbn VoIP?

Compatibility varies by provider, ATA, fax device and configuration. T.38 support or an online fax service may help, but the business should test both sending and receiving before relying on fax for a critical process.

Can I connect a fire alarm, lift phone or medical alarm to an ATA?

Do not do so without confirmation from the organisation responsible for the device or monitoring service. That organisation should specify the supported connection, power arrangement and test procedure.

Can I keep my business phone number when changing providers?

Eligible local, mobile, 13, 1300 and 1800 numbers can be portable under ACMA rules, subject to the applicable process and the gaining provider accepting the request. Keep the current service active, make sure the account details match and obtain a written migration schedule.

Does a business with basic ISP-managed VoIP need to upgrade?

No automatic upgrade follows from the PSTN transition. Keeping the service can be reasonable if it meets requirements for call capacity, voicemail, forwarding, after-hours handling, mobile answering, multiple users, resilience, support and attached devices.

Is ISDN shutdown still an urgent general deadline in 2026?

Mainstream ISDN migration is historical rather than a new general 2026 deadline. If an unusual legacy or Special Service remains, identify the exact carrier product and seek provider-specific advice before selecting a replacement.