SIP Trunking Australia
SIP trunking connects your existing phone system to the internet, replacing old phone lines with flexible, cheaper VoIP capacity.
Key Features
Replace Old Lines
SIP trunks do the job of legacy copper phone lines over the internet.
Pay for Capacity
Scale your number of channels up and down as call volumes change.
Keep Your PBX
Connect your existing phone system instead of replacing it outright.
Cheaper Calls
VoIP rates are typically lower than traditional line pricing.
Works with 1300
Route 1300 and 1800 calls through your trunk like any other line.
Flexible Numbers
Add local and national numbers on the same trunk as you grow.
Ready to get started?
Get StartedSIP trunking is the technology that keeps existing phone systems alive and relevant in a VoIP world. Instead of paying for old-style lines, a SIP trunk carries your calls over the internet. For an overview of hosted options, including when you do not need your own system at all, see our hosted VoIP and PABX page.
What Is SIP Trunking?
SIP stands for Session Initiation Protocol — the standard used to set up voice calls over the internet. A SIP trunk is the virtual equivalent of a traditional phone line: it connects your business to the telephone network, but over your data connection rather than copper. You get the calls without the line rental of the old network.
How SIP Trunking Works
Your existing PBX or phone system connects to a SIP provider, who carries calls to and from the public telephone network. Each trunk carries a number of channels, where a channel is roughly one concurrent call. When someone calls your business number, the trunk connects them to your system, and outbound calls travel the same way.
Benefits of SIP Trunks
- Lower cost — VoIP rates and shared infrastructure usually beat legacy line pricing.
- Flexibility — add channels for peak times and remove them when things quieten down.
- One connection — your data and voice share the internet link instead of needing separate lines.
- Future-proofing — when the old network is wound down, SIP keeps your hardware working.
What It Costs
SIP trunking is priced per channel per month, plus your call rates. Because you choose the number of channels, you only pay for the capacity you actually use. For businesses that prefer to rent the whole system instead of running their own, hosted VoIP bundles everything into one simple monthly fee — see our cloud phone system page for how that works.
SIP vs Hosted VoIP
SIP trunking keeps your existing PBX and connects it to VoIP. A hosted VoIP system removes the PBX altogether and runs everything in the cloud. If you have a good phone system you want to keep, SIP trunking is the cost-effective path. If you want to shed the hardware and management, hosted VoIP is usually the better fit.
Frequently Asked Questions
- Do I need new phones for SIP trunking? If your existing PBX supports SIP, you can keep your current handsets and connect them via the trunk.
- How many channels do I need? Roughly the number of calls you want to handle at once. A sales team of ten might need eight to ten channels, for example.
- Can I use it with my 1300 number? Yes. 1300 and 1800 numbers route through SIP trunks like any other inbound call.
- What happens when the old network closes? SIP trunks already run over the internet, so you are unaffected by legacy network shutdowns.
Not sure whether SIP trunking or a full hosted system suits you? Compare your options in our hosted VoIP provider comparison.