Your Phone System Is Holding Your Business Back. It's Time to Fix That.
We migrate, manage and support your entire business voice infrastructure — VoIP, Cloud PBX, Microsoft Teams Voice and more — with zero disruption to your team.
Teams Calling Integration
Unified enterprise calling directly inside Microsoft Teams
C9 Cloud Phone System
Cloud PBX with 100+ business voice features
Contact Centre (CCaaS)
Omni-channel supervisor and queue controls
SIP Trunking Core
Connect legacy hardware to our low-latency SIP network
Inbound Numbers (1300/1800)
Advanced landing and time-of-day routing patterns
Safe Number Porting
Zero downtime transition for your business numbers
AI Routing & Auto-Attendants
Smart IVRs and conversational call guides
Teams Calling Integration
Unified enterprise calling directly inside Microsoft Teams
C9 Cloud Phone System
Cloud PBX with 100+ business voice features
Contact Centre (CCaaS)
Omni-channel supervisor and queue controls
SIP Trunking Core
Connect legacy hardware to our low-latency SIP network
Inbound Numbers (1300/1800)
Advanced landing and time-of-day routing patterns
Safe Number Porting
Zero downtime transition for your business numbers
AI Routing & Auto-Attendants
Smart IVRs and conversational call guides
Why Australian Businesses Trust Us With Their Voice
C9 replaces legacy PBX hardware and old carrier links with direct direct-routing paths under a fully managed onshore onshore support scope.
PSTN/ISDN Migration Specialists
We've completed 500+ migrations across Australia. We handle the entire process — porting, cutover and testing — with zero downtime guaranteed.
Significant Cost Savings
Businesses switching from legacy systems save an average of 40% on their monthly call costs. We'll show you the numbers before you commit.
Microsoft Teams Voice Experts
We're certified in Teams Direct Routing. If your team already lives in Teams, we'll make your phone system live there too.
Fully Managed Service
Moves, adds, changes, porting, support — all handled by us. Your team picks up the phone. We handle everything behind it.
Carrier-Agnostic
We're not tied to one provider. We select the right voice carrier for your call volumes, locations and budget.
Compliance-Ready
Call recording, audit trails, and data sovereignty options for healthcare, legal and financial services businesses.
Telstra is switching off ISDN and PSTN. Are you ready?
Thousands of Australian businesses are still on legacy phone systems that will stop working. Book a free migration assessment before it\'s too late.
The Smarter Way to Manage Business Voice
See why Australian businesses chose managed voice over the alternatives.
| Feature | Staying on Legacy PSTN | Going Direct to Telco | ✅ Our Managed Voice |
|---|---|---|---|
| PSTN shutdown ready | ✕ | ✕ | |
| Number porting handled | ✕ | ✕ | |
| Call cost savings | ✕ | ✕ | |
| Microsoft Teams integration | ✕ | ✕ | |
| 24/7 support | ✕ | ✕ | |
| Call recording & compliance | ✕ | ✕ | |
| Moves adds changes | ✕ | ✕ | |
| Single invoice | ✕ | ✕ |
Trusted by Australian Businesses to Keep Them Connected
"We had no idea the PSTN shutdown would affect us this soon. They migrated our entire phone system across 8 locations in under two weeks. Zero downtime. Incredible."
"Our call costs dropped by 43% in the first month after switching to their managed VoIP. We wished we'd done it years ago."
"The Teams Voice integration was seamless. Our team didn't even notice the change — they just suddenly had a proper phone system inside Teams."
How We Migrated an 8-Site Accounting Firm Off ISDN With Zero Downtime
The Problem
A national accounting firm with 8 offices was still running on ISDN lines. With the Telstra PSTN shutdown looming, they needed a full migration to cloud voice — without disrupting client calls during tax season.
Our Solution
Deployed a fully managed Cloud PBX with Microsoft Teams Direct Routing across all 8 sites. Ported all existing numbers, configured auto attendants and call routing, and conducted staff training. Entire migration completed in 11 days.
The Result
Complete 100% migration before PSTN shutdown deadline, substantial voice rate cost reductions, and native Teams Calling features setup across all regional branches.
Our Voice Technology Partners
We work with the leading voice platforms to deliver the right solution for your business.
Managed Voice Frameworks Engineered for Your Use Case
Don't wait until your phones stop working
The Telstra PSTN and ISDN network is being shut down. If your business is still on legacy lines, you need a migration plan now. We've completed 500+ migrations across Australia with zero downtime guaranteed.
Get Your Free Voice Audit
Find out if your phone system is costing you more than it should — and whether you\'re ready for the PSTN shutdown.
Full review of your current phone system
Review Extensions, inbound call queues, and lines setups.
PSTN/ISDN migration readiness assessment
Determine if copper lines shutoff will impact your operational branches.
Cost comparison vs your current setup
Scanning active plans to calculate direct voice cost savings.
Response within 1 business day
Our onshore voice engineers review details and follow up fast.
Frequently Asked Questions
Yes, absolutely. We manage the full number porting logistics safely with current carriers to ensure all local numbers, indials, and 1300 inbound routes transfer with zero downtime.
Why leaders trust C9 Communications
"Consolidating our nationwide connectivity and IT infrastructure under C9 Communications was the best strategic move we made. Their enterprise Fibre Business nbn® eliminated our downtime, and having a single, proactive Australian support team means zero IT headaches."
David Chen
Operations Director
"C9 executed a flawless migration of our staff to Microsoft 365 while completely hardening our security posture. Their zero-touch device deployment via Intune saved our IT team hundreds of setup hours and standardized our hybrid workforce seamlessly."
Sarah Jenkins
Chief Technology Officer
"The strategic roadmap provided by C9 aligned our technology stack perfectly with our aggressive growth targets. They don't just fix issues; they engineer sophisticated, centralized infrastructure that scales dynamically. Truly unmatched enterprise consultancy."
Michael Ross
Managing Director
"Consolidating our nationwide connectivity and IT infrastructure under C9 Communications was the best strategic move we made. Their enterprise Fibre Business nbn® eliminated our downtime, and having a single, proactive Australian support team means zero IT headaches."
David Chen
Operations Director
"C9 executed a flawless migration of our staff to Microsoft 365 while completely hardening our security posture. Their zero-touch device deployment via Intune saved our IT team hundreds of setup hours and standardized our hybrid workforce seamlessly."
Sarah Jenkins
Chief Technology Officer
"The strategic roadmap provided by C9 aligned our technology stack perfectly with our aggressive growth targets. They don't just fix issues; they engineer sophisticated, centralized infrastructure that scales dynamically. Truly unmatched enterprise consultancy."
Michael Ross
Managing Director
"Consolidating our nationwide connectivity and IT infrastructure under C9 Communications was the best strategic move we made. Their enterprise Fibre Business nbn® eliminated our downtime, and having a single, proactive Australian support team means zero IT headaches."
David Chen
Operations Director
"C9 executed a flawless migration of our staff to Microsoft 365 while completely hardening our security posture. Their zero-touch device deployment via Intune saved our IT team hundreds of setup hours and standardized our hybrid workforce seamlessly."
Sarah Jenkins
Chief Technology Officer
"The strategic roadmap provided by C9 aligned our technology stack perfectly with our aggressive growth targets. They don't just fix issues; they engineer sophisticated, centralized infrastructure that scales dynamically. Truly unmatched enterprise consultancy."
Michael Ross
Managing Director