Hosted PBX or SIP?

Guest Blogger
Hosted PBX or SIP?

ISDN (Integrated Services Digital Network), one of the staples of communications for Australian businesses is nearing its end-date, raising the question of how to maintain those essential fixed voice calling and Phone System/PBX capabilities critical to business.

What is ISDN?

ISDN is a dedicated network that delivers multiple voice lines over a single physical connection, usually copper lines, to many businesses in Australia. The ISDN connection terminates onto a PBX/Phone System at the business site which in turn connects to multiple telephone handsets at that site.

As part of Telstra’s big deal signed with the NBN Co a few years ago, the incumbent carrier has agreed to decommission Australia’s entire copper network by 2022.

Accordingly, the carrier stopped selling ISDN2, ISDN2 Enhanced, ISDN10/20/30, DDS Fastway, Megalink and Frame Relay products last year, ahead of the products being switched off.

And while 2022 might seem a long way away, if you’re in a business of any size or reach, the task of rebuilding your entire business phone system, including porting numbers and all the other related tasks, isn’t something you want to be doing on the hop.

Here’s a summary of the key dates involved in the programme:

  • 31st January 2018 – New ISDN service unavailable for customers who do not already have ISDN in place
  • 30th June 2018 – Full cease sale on new or additional ISDN services for all customers. No new services will be available
  • June 2019 – Disconnection will commence for existing ISDN connections
  • By 2022 – All ISDN connections will be disconnected, and the full network will be decommissioned.

What’s next?

The choice is to replace ISDN with one of two options:

  1. Replace ISDN and all dedicated Phone System/PBX hardware with a Hosted PBX which provides voice calls in and out along with call routing, IVR and voicemail on subscription model, including a modern handset and even Mobile App.


  1. Replace ISDN lines with SIP Trunks over a data network connection and upgrade or replace your dedicated Phone System/PBX along with handsets to be compatible.

What used to be thought of as traditional telephony services are now increasingly moving to a hosted model whereby PBX and UC (unified communications) are hosted and delivered entirely in the Cloud. This means no need to buy and manage PBX hardware on premise at all.

What is a SIP Trunk?

SIP trunking (or SIP trunks for short) is a public IP telephony service that’s based on ‘session initiated protocol lines’.

SIP is delivered over data lines that are used for internet and Wide Area Network (WAN) connections – which you’ve more than likely already got. By merging voice as another application on these data lines, the existing analogue or ISDN lines are no longer needed. SIP “lines” are automatically created and removed as required.

So which one is right for your business?

Hosted PBX/Phone System

Business locations that do not require highly advanced contact centre functionality are the best place to move to a fully hosted PBX/Phone System solution, more information here

SIP with Modern PBX

Business locations that have very specific, highly advanced contact centre functions, agent level reporting, integrations with various business systems etc. are better suited for an on-premise solution with hardware, software and SIP trunk to connect to the global voice network.

ISDN is being switched off, yes. And while it has been an extremely important technology for a long time, the new generation of digital IP and cloud-based technologies allow for more flexible, sophisticated and affordable solutions that will continue to evolve and improve long after the copper network is decommissioned.

If you’re concerned about preparing for the 2022 switch-off date, and / or are interested in exploring the range of digital telephony options, our expert team of IT&T engineers are available to help build the right plan for your organisation.

Find out more information about business telecom options, or talk to the experts here

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