SIP Trunks
Save 30–50% on Phone Bills
Replace expensive ISDN lines with modern SIP trunks. Scale your business communications, reduce costs, and gain unlimited concurrent calls. ClearCall handles the entire migration with zero downtime. Trusted by businesses across Toowoomba, Ipswich, and Queensland.
Cost Savings
Concurrent Calls
Support Available
Why Choose ClearCall SIP Trunks?
Modern SIP trunking that combines cost savings with enterprise-grade reliability and security.
Save 30–50% on Phone Bills
Eliminate expensive ISDN line rentals and reduce call costs with per-second billing.
Unlimited Concurrent Calls
Scale your call capacity instantly without adding expensive hardware or lines.
Australian Number Porting
Keep your existing phone numbers or get new Australian numbers (02, 03, 07, etc.).
Enterprise Security
End-to-end encryption, compliance with Australian telecom standards, and DDoS protection.
Redundant Failover
4G/5G backup connectivity ensures your business stays connected if internet fails.
No Setup Fees
Get started immediately with no installation fees, hardware costs, or long-term contracts.
ISDN vs SIP Trunks: The Comparison
See why modern businesses are replacing ISDN with SIP trunks.
| Feature | ISDN Lines | SIP Trunks |
|---|---|---|
| Setup Cost | High (hardware + installation) | Low (software-based) |
| Monthly Line Rental | $50– 00 per line | From $8 per month |
| Call Cost | Fixed per minute | Per-second billing (lower rates) |
| Scalability | Limited (requires new hardware) | Unlimited (software-based) |
| Remote Work Support | Poor (requires VPN) | Excellent (cloud-native) |
| Integration | Limited | Integrates with CRM, Teams, Outlook |
What You Get With ClearCall SIP Trunks
- Replace ISDN lines with modern, cost-effective SIP trunks
- Support for unlimited concurrent calls with scalable capacity
- Per-second billing — pay only for what you use
- Seamless integration with existing PBX systems
- Australian number porting with no downtime
- 24/7 managed support and proactive monitoring
- 4G/5G failover for business continuity
- Advanced features: call recording, call queuing, IVR, and more
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Ready to Migrate to SIP Trunks?
Our team will handle the entire migration from ISDN to SIP trunks, including number porting, system configuration, and staff training. Zero downtime, maximum savings.
Our SIP Trunks Migration Process
From assessment to go-live, we manage every step of your ISDN to SIP migration.
Assessment
We evaluate your current system, call volume, and requirements to design the right solution.
Number Porting
Port your existing Australian numbers to SIP trunks with no downtime.
System Configuration
Configure your PBX or 3CX system to work with SIP trunks and set up redundancy.
Testing & Validation
Thoroughly test all call flows, failover scenarios, and integrations.
Go-Live & Training
Switch to SIP trunks with on-site support and staff training.
Frequently Asked Questions
Everything you need to know about SIP trunks and ISDN replacement.
What are SIP trunks and how do they work?
SIP trunks are virtual phone lines that replace traditional ISDN lines. They use your internet connection to make and receive calls, converting voice into digital data. SIP stands for Session Initiation Protocol — the technology that powers modern VoIP communications.
How much can we save by switching from ISDN to SIP trunks?
Most businesses save 30–50% on phone bills by switching from ISDN to SIP trunks. ISDN lines are expensive to rent and maintain, while SIP trunks are billed per-second with no line rental fees.
Do SIP trunks work with our existing phone system?
Yes, SIP trunks work with most modern PBX systems, including 3CX, Avaya, Cisco, and many others. ClearCall can integrate SIP trunks with your existing system or help you migrate to a modern 3CX system.
What happens if our internet goes down?
ClearCall provides redundant failover options, including 4G/5G backup connectivity. If your primary internet connection fails, calls automatically route through the backup connection, ensuring your business stays connected.
Ready to Replace ISDN and Save on Phone Bills?
Get a free quote and learn how much you can save with SIP trunks. Our team will handle the entire migration with zero downtime.