What is SIP Trunking?
SIP trunks are virtual phone lines that carry voice calls over your internet connection. They connect any SIP-capable phone system to the public telephone network at a fraction of the cost of traditional phone lines.
You keep your handsets, your call flows and your phone numbers. All that changes is the lines coming into your system — and your monthly bill.
Each SIP channel supports one concurrent call. A business with 5 channels can make or receive 5 simultaneous calls. Add or remove channels instantly — no hardware changes required.
Caznet SIP trunks run on our carrier-grade voice platform, hosted in our Adelaide data centre and supported by a local team — not an overseas call centre.
$34.95 per channel, per month
One simple price — local, national, mobile and 1300 calls included. Add as many channels as your business needs. No tiers, no bundles, no lock-in.
| Call type | Cost |
|---|---|
| Local & National | Included |
| Australian mobile | Included |
| International | On request |
Fair use policy and Acceptable Use Policy apply. These plans are not suitable for call centres, telemarketing, auto-dialling, or any form of high-volume calling. See Critical Information Summary for full terms.
| Additional AU DID number | $1 / mth |
| NZ DID number | POA |
| Number porting | First port free |
You need one channel for each call your business can make or receive simultaneously. As a rule of thumb, a 10-person office typically needs 4–6 channels. Not sure? Call us and we'll work it out with you — and you can always add more channels instantly if your needs change.
We port your numbers from your current provider as part of the switchover. Your customers keep dialling the same number. The first port is always free.
Two things to check before switching
SIP trunks work with most modern phone systems and broadband connections. Here's what to confirm before you get started.
1. A SIP-compatible phone system
You'll need a phone system that supports SIP. This includes on-premise PBX, cloud PBX and most modern business phone systems — including 3CX, FreePBX, Avaya, NEC and Panasonic. Older systems may need a line card or SIP gateway adapter.
Not sure if your system is compatible? Call us and we'll check it for you.
2. A suitable internet connection
Each concurrent call uses roughly 100 Kbps of bandwidth. A standard NBN connection handles most businesses comfortably — an NBN 50 or 100 plan is suitable for up to 10–15 simultaneous calls.
For higher call volumes or mission-critical voice, we can pair your SIP trunks with a dedicated internet service with QoS priority for voice traffic.
SIP trunks backed by an Adelaide team
Carrier-grade voice platform, hosted in our Adelaide data centre. Local support — not a distant call centre.
Talk to a specialist →100% SA support
Adelaide-based team handles everything — no overseas call centres.
Keep your existing numbers
We port your current numbers as part of the switchover. First port is always free. No disruption to incoming calls.
No lock-in contracts
Month-to-month. Add or remove channels instantly. No penalties, no paperwork.
Works with your existing PBX
Keep your handsets and call flows. SIP trunks just replace the lines — nothing else changes.
All calls included
Local, national, mobile and 1300 calls are included in your monthly plan. Fair use and Acceptable Use Policy apply.
Built-in failover
If your primary internet connection goes down, your SIP trunks can automatically fail over to a backup connection or mobile — keeping your phones live.
Caznet vs. national providers
Most national SIP trunk providers charge three times more per channel, bill calls per minute and lock you into long contracts — often from interstate with offshore support. Here's how Caznet compares.
Common questions
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A SIP trunk is a virtual phone line that carries voice calls over your internet connection, connecting any SIP-capable phone system to the public telephone network via Caznet's carrier-grade voice platform. Each channel supports one concurrent call — a business with 5 channels can make or receive 5 simultaneous calls.
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In most cases, yes. Caznet SIP trunks work with any SIP-capable phone system — on-premise PBX, cloud PBX or hosted systems — including 3CX, FreePBX, Avaya, NEC and Panasonic. Our team will confirm compatibility before proceeding. If your system doesn't support SIP natively, an Analog Telephone Adapter (ATA) or SIP gateway may be required — we'll advise either way.
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One channel per simultaneous call. A 10-person office typically needs 4–6 channels. Our team will review your call patterns and recommend the right number — and you can always add more instantly if demand changes.
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Yes. We port your existing geographic numbers (e.g. 08 XXXX XXXX) to Caznet SIP trunks. Your first port is free. The porting process is managed entirely by our team and is typically completed within 2–5 business days. Your existing numbers remain active throughout — there is no disruption to incoming calls.
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Caznet SIP Trunking supports failover — if your primary internet connection goes down, your trunks can automatically switch to a backup connection and keep your phones running. We configure this as part of your setup. We can also supply backup internet connectivity for businesses that require maximum resilience.
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Yes. If you'd prefer to replace your entire phone system rather than just the lines, our Cloud Hosted PBX is a fully managed alternative — new handsets, hosted call management, free installation and training included. Talk to us and we'll recommend the right solution for your situation.
Legal documents
Key legal and policy documents for Caznet SIP Trunks.
Ready to replace your old phone lines?
Tell us how many lines you need and what system you're running — we'll have you switched over without disrupting your business.