End of an Era: ISDN Disconnection due to NBN Phone Systems

NBN Phone Systems: Is ISDN Being Disconnected?

NBN is progressively designing and manufacturing new fibre extensions for all eligible areas across Australia. Recently, they announced that over 900,000 homes are now eligible for a fibre upgrade and have opted into selected plans. Furthermore, their goal was to reach 2 million premises by the end of 2023.

But what is NBN? And is ISDN being phased out because of it?

According to NBN, the current phone service system — ISDN — is outdated and increasingly difficult to maintain. These days, most people prefer communication through VoIP phone systems or platforms like Skype, Teams, and Zoom.

So now, we have the NBN — the National Broadband Network.

Naturally, this raises more questions. For example:

•  Will NBN replace my current internet cable?
• Are NBN phone systems essential for business communication?
• And can I use a VoIP phone system as an ISDN alternative?
  

This article answers all your questions about ISDN, VoIP, and NBN phone systems.

What is ISDN?

ISDN stands for Integrated Services Digital Network. It runs on copper wire networks and enables voice and data services to be delivered simultaneously via digital lines. Compared to its predecessor (PSTN), ISDN was once considered fast, with speeds of up to 128 Kbps.

What is NBN?

NBN, or the National Broadband Network,  is a government-owned corporation that aims to upgrade Australia’s outdated internet and phone infrastructure. This upgrade involves the installation of NBN phone systems in homes and businesses nationwide.

While ISDN relies on copper wires to transmit data, NBN operates through fibre networks. These modern NBN phone systems provide both internet and voice services via a single data line. NBN is also committed to delivering both wired and wireless communication options.

Is ISDN Being Disconnected Due to NBN?

In short, yes, ISDN is being disconnected due to the NBN rollout.

Before the introduction of NBN, ISDN was widely used and reliable. However, with faster and more reliable technologies such as VoIP and NBN, ISDN has become obsolete. NBN phone systems offer higher speeds and simpler standardisation, making the continued use of ISDN impractical.

The internet has become a fundamental part of both business and personal life. That’s why NBN is replacing old systems like ISDN and PSTN with fibre-optic technology. If you’re currently connected via ISDN, your system will likely be phased out soon.

To check availability, visit the official NBNCo website and confirm whether NBN is accessible in your area.

When Will ISDN Disconnection Happen?

The NBN disconnection process has already begun.

In its IP program updates, NBN confirmed it’s an ambitious transition, aiming to have all Australians using IP-based communications by the end of 2025.

Telstra initiated ISDN disconnection as early as September 2019 and announced the complete shutdown of these services by the end of 2022. Services impacted include:

• ISDN2
  
• ISDN2 Enhanced
  
• ISDN10/20/30
  
• DDS Fastway
  
• Frame Relay
  
• Megalink
  

Additionally, Openreach ran NBN phone system trials in Salisbury and Mildenhall, ceasing the sale of ISDN and PSTN services before the trial concluded in 2022.

How Will ISDN Disconnection Affect Businesses?

The new IP network operates quite differently from the traditional analogue network. If your business relies on special service equipment that runs on PSTN or ISDN,  like fire alarms, security systems, or BDSL Ethernet, these may stop functioning.

You can view a list of affected services on the NBN’s official website. If you’re still using ISDN-based equipment, ensure it’s compatible with the new infrastructure.

Businesses in ISDN Melbourne zones should be especially alert, as many disconnections are already underway. Delaying the switch may risk service interruptions and revenue loss.

What Should Businesses Do Before ISDN Disconnection?

Australia is one of the first countries to actively adopt NBN phone systems. Businesses need to prepare to avoid service disruptions.

Here are the key steps you should follow:

1. Understand Your Technical Environment

• How do you currently handle calls?
  
• How do you access the internet?
  
• What does your phone system setup look like?
  
• Have you backed up essential business data and contacts?
  
• Do you need remote communication capabilities?
  
• Will you require new hardware like VoIP phones?
  
• Are video conferencing or fax systems part of your workflow?
  

By answering these questions, you’ll gain clarity on your business needs and why transitioning is important.

2. Execute Your Migration Plan

Now that you’ve evaluated your systems and requirements, it’s time to act. Plan your migration based on budget, schedule, risk level, and operational demands.

Consider appointing a project manager or outsourcing to a migration expert. Doing so can significantly reduce risks, lower costs, and save valuable time.

Why VoIP is a Great ISDN Alternative

Since NBN disconnection might cause brief downtime during installation, many businesses are exploring VoIP as a seamless ISDN alternative.

VoIP (Voice over Internet Protocol) is cloud-based, so you don’t need copper wires to connect. A stable internet connection is all you need. VoIP systems are affordable, scalable, and flexible, making them ideal for modern businesses.

ISDN Melbourne businesses have already begun transitioning to VoIP as a smarter, more adaptable option.

Final Thoughts: NBN Phone Systems Are the Future

ISDN disconnection has certainly shaken up the telecom landscape, especially for businesses. But NBN phone systems offer a reliable, high-performance solution if you plan.

When needed, VoIP serves as an excellent backup or even a permanent ISDN replacement, offering the flexibility and efficiency your business demands.

If you haven’t yet prepared, now’s the time. Because in Australia, the future of communication is already here.

Frequently Asked Questions

1. Will I lose my current phone number when ISDN is disconnected?

Not necessarily, but you must act before the disconnection. To keep your number, you need to “port” it to a VoIP or SIP provider. If the ISDN service is shut down before the porting process is complete, the number may be permanently lost or placed in a “quarantine” period, making it very difficult to recover.

2. How much time do I have to switch once NBN is available?

Generally, you have an 18-month window from the time your area is declared “Ready for Service” by NBN Co. However, for specific “Special Services” like ISDN, there are fixed managed disconnection dates that may differ from the standard residential rollout. It is best to start the migration at least six months before your deadline.

3. Will my existing office PBX system still work?

Traditional PBX systems designed only for ISDN will stop working unless they are IP-compatible. If your system is older, you may need an ISDN-to-SIP converter (gateway) to connect it to the NBN, or you may choose to upgrade to a modern Cloud-hosted PBX system, which offers more features and flexibility.

4. Are there any other services affected besides my phone?

Yes. Any service that uses a traditional copper line can be impacted. This includes:

• Security & Fire Alarms: Monitored alarms may fail to signal the home base.
• Lift Phones: Emergency phones in elevators often rely on these lines.
• EFTPOS Terminals: Older machines may lose their connection for processing payments.
• Fax Machines: Traditional faxing requires a digital adapter to work over NBN.

5. Is SIP trunking better than the old ISDN?

For most businesses, yes. SIP trunking is more cost-effective, often saving 50–70% on line rentals and call costs. It is also far more flexible; you can add or remove phone “lines” (channels) almost instantly without needing a technician to visit and install physical wiring.