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Connect your existing on-premise or cloud PBX to our Tier-1 Australian voice network. Click2Call SIP Trunks deliver superior call quality, redundancy, and scalability, replacing your outdated ISDN lines with a flexible, cost-effective VoIP solution. Keep your PBX, keep your numbers, and upgrade your connectivity.
Key Takeaways
A SIP Trunk is the modern, digital equivalent of a traditional telephone line. Instead of a physical copper wire running to your building, a SIP trunk uses your business internet connection to link your phone system (PBX) to the public telephone network. 'SIP' stands for Session Initiation Protocol, which is the open-standard technology that establishes and manages voice calls over the internet (VoIP).
Replacing ISDN and Analogue Lines
For decades, businesses relied on ISDN (Integrated Services Digital Network) or older analogue PSTN lines to make and receive calls. These technologies are now obsolete and being phased out across Australia as part of the NBN rollout. A SIP trunk is the direct replacement. It provides the same functionality—making and receiving multiple calls at once—but does so more efficiently and cost-effectively over your data connection. Each 'channel' in a SIP trunk allows for one concurrent call, so a 10-channel SIP trunk is the equivalent of 10 traditional phone lines.
Eliminate expensive ISDN line rentals and enjoy lower call rates.
Scale your call capacity up or down in minutes, not weeks.
Route calls to backup numbers or locations instantly if your PBX goes offline.
Use any local number from any Australian city, regardless of your physical location.
Bring your numbers or get new ones from any area code.
Automatic failover across multiple Tier-1 voice carriers.
Keep all your existing business phone numbers.
Terminate your national inbound numbers to your PBX.
Only pay for what you use with fair, per-second billing on calls.
Connects directly to your existing IP-enabled PBX.
Certified for use with 3CX, FreePBX, Asterisk and more.
Get help from our expert team based in Australia.
| Feature | Traditional Lines (ISDN) | Click2Call SIP Trunks |
|---|---|---|
| Technology | Physical copper lines | Virtual lines over internet (VoIP) |
| Scalability | Slow, requires new line installation | Instant, add channels on demand |
| Cost | High monthly rental per line | Low monthly cost per channel |
| Disaster Recovery | Difficult, tied to physical location | Easy, instantly re-route numbers |
| NBN Readiness | Not compatible, being phased out | NBN-native technology |
Our SIP trunks are built on open standards, ensuring compatibility with any SIP-enabled IP PBX.
3CX
FreePBX
Asterisk
Cisco
Avaya
Yealink
Grandstream
A SIP (Session Initiation Protocol) trunk is a virtual phone line that connects your business phone system (PBX) to the Public Switched Telephone Network (PSTN) via the internet. Instead of traditional copper phone lines, SIP trunks use your existing internet connection to carry voice calls, enabling significant cost savings and greater flexibility.
Each SIP channel supports one simultaneous call. As a general rule, you need roughly one channel for every 3–4 staff members who make calls concurrently. For example, a business with 20 staff might need 5–8 channels. Click2Call can help you assess your call volume and recommend the right number of channels.
Yes. Click2Call supports full number porting for Australian geographic numbers (02, 03, 07, 08 prefixes), 1300 numbers, and 1800 numbers. Our team manages the entire porting process, which typically takes 5–10 business days.
Click2Call SIP trunks are compatible with all major IP PBX systems, including 3CX, FreePBX, Asterisk, Cisco, Avaya, Grandstream, and Yealink. If you are unsure whether your existing PBX is compatible, contact our team and we will confirm compatibility before you sign up.
No. Click2Call SIP trunks are available on a month-to-month basis with no lock-in contracts. You can add or remove channels at any time through the customer portal, and you only pay for what you use.
A standard NBN connection is sufficient for most businesses. Each SIP channel requires approximately 100 kbps of bandwidth. We recommend a connection with low latency and jitter for optimal call quality. A dedicated internet connection or QoS (Quality of Service) configuration is recommended for businesses with high call volumes.
Yes. Click2Call SIP trunks are available to any Australian business with an internet connection. We provide Australian geographic numbers for all states and territories, as well as 1300 and 1800 numbers.
New SIP trunk services can typically be provisioned within 24 hours for new numbers. If you are porting existing numbers, the process takes 5–10 business days. Our team will guide you through the setup and configuration.
A SIP trunk connects your existing on-premise or hosted PBX to the telephone network. A Cloud PBX replaces your entire phone system with a fully hosted solution in the cloud. If you already have a PBX you are happy with, SIP trunks are the most cost-effective way to modernise your calling. If you want a complete, managed phone system, a Cloud PBX is the better choice.
Yes. Click2Call offers a 30-day free trial for all services, including SIP trunks. You can sign up at portal.click2call.com.au/join and our team will assist with the initial configuration and testing.
Move to a more flexible, reliable and cost-effective voice solution. Talk to our team about a custom quote.
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