Replace legacy ISDN and copper phone services with modern managed SIP connectivity. C9 handles the migration of your existing PBX, cloud voice, or Microsoft Teams environment with full number continuity and failover protection.
Aging ISDN systems and unreliable providers create hidden business risk. Safely modernise your voice delivery today.






















Replace legacy constraints with modern voice reliability. Identify the strategic drivers for modernising your calling environment.
Aging ISDN/Copper systems are end-of-life and increasingly unreliable.
Unexpected outages and high maintenance costs.
Transition to resilient IP-based voice with C9 managed SIP.
Fear of losing established business phone numbers during migration.
Loss of customer contact and brand disruption.
Expert managed number porting ensures full continuity.
Legacy PBX hardware that isn't ready to be fully retired.
Fragmented systems and limited cloud capability.
Connect your current PBX to the modern voice core via SIP.
Lack of redundancy in case of local network or provider failure.
Total communication blackout during an incident.
Built-in automated failover routing for constant uptime.
Disconnected systems while transitioning to modern workplace apps.
Inefficient workflows and user frustration.
Seamlessly bridge your voice services into Microsoft Teams.
Scaling limitations with legacy line-based systems.
Busy signals and lost sales opportunities.
Instantly scale call capacity to match your business growth.
A structured path from legacy constraints to modern voice reliability. We manage every step to protect your business continuity.
We conduct a thorough audit of your current PBX hardware, line types, and phone number ranges. Identifying every dependency is critical for a safe migration.

We design redundant voice pathways so your calls never drop. If your primary network fails, our managed SIP core automatically reroutes calls to secondary paths.
Automated failover ensures your inbound customer calls reach your team even during local site disasters or internet outages.
We manage the porting of your existing numbers from legacy ISDN into the SIP core. Our engineers own the go-live process, ensuring a zero-disruption cutover.

"We replace executive uncertainty with technical clarity. When voice delivery is managed correctly, it simply works."
Stop juggling hardware vendors and carriers. C9 provides a single point of accountability for your entire calling environment — from the core network to your desktop.
C9 helps Australian businesses modernise voice environments while protecting number continuity, business uptime, and operational communication reliability.
Reliable communication requires complete infrastructure control. Explore the solutions that integrate seamlessly.
Interested in replacing legacy ISDN or improving your PBX reliability? Our specialists provide technical strategy and managed migration support.
Call us today: 1800 000 299
Not a call centre. Not a script. Someone who actually knows IT.
We show you exactly where your infrastructure is exposed.
Plain English. Exact pricing. No lock-in or pressure.
Select your preferred engagement path below.
Yes. We manage the entire number porting process, ensuring you maintain complete continuity with your customers without interruption.
"We used to spend hours chasing different providers whenever a store lost connectivity. Now we call one team, they understand the full environment, and they own the issue through to resolution."
National Retail Group
"Our clinicians cannot wait for technology problems to be passed between vendors. C9 stabilised the network, improved visibility across our clinics, and gave our team a clear escalation path."
Multi-site Healthcare Group
"The biggest change is visibility. We can see what is happening across sites, understand recurring issues, and make infrastructure decisions before they become operational problems."
National Distribution Business
"C9 replaced a collection of disconnected suppliers with one practical technology roadmap. Support is faster, responsibilities are clear, and our leadership team finally has confidence in the plan."
Professional Services Firm
"Reliable warehouse connectivity is business-critical for us. C9 redesigned the network around how our teams actually work, removed the dead zones, and now proactively manages performance."
Logistics & Warehousing Group
"The commercial value is not just lower supplier overhead. We now have predictable costs, clearer reporting, and a partner who explains where investment will make the biggest operational difference."
Growing Australian Business
"We used to spend hours chasing different providers whenever a store lost connectivity. Now we call one team, they understand the full environment, and they own the issue through to resolution."
National Retail Group
"Our clinicians cannot wait for technology problems to be passed between vendors. C9 stabilised the network, improved visibility across our clinics, and gave our team a clear escalation path."
Multi-site Healthcare Group
"The biggest change is visibility. We can see what is happening across sites, understand recurring issues, and make infrastructure decisions before they become operational problems."
National Distribution Business
"C9 replaced a collection of disconnected suppliers with one practical technology roadmap. Support is faster, responsibilities are clear, and our leadership team finally has confidence in the plan."
Professional Services Firm
"Reliable warehouse connectivity is business-critical for us. C9 redesigned the network around how our teams actually work, removed the dead zones, and now proactively manages performance."
Logistics & Warehousing Group
"The commercial value is not just lower supplier overhead. We now have predictable costs, clearer reporting, and a partner who explains where investment will make the biggest operational difference."
Growing Australian Business
"We used to spend hours chasing different providers whenever a store lost connectivity. Now we call one team, they understand the full environment, and they own the issue through to resolution."
National Retail Group
"Our clinicians cannot wait for technology problems to be passed between vendors. C9 stabilised the network, improved visibility across our clinics, and gave our team a clear escalation path."
Multi-site Healthcare Group
"The biggest change is visibility. We can see what is happening across sites, understand recurring issues, and make infrastructure decisions before they become operational problems."
National Distribution Business
"C9 replaced a collection of disconnected suppliers with one practical technology roadmap. Support is faster, responsibilities are clear, and our leadership team finally has confidence in the plan."
Professional Services Firm
"Reliable warehouse connectivity is business-critical for us. C9 redesigned the network around how our teams actually work, removed the dead zones, and now proactively manages performance."
Logistics & Warehousing Group
"The commercial value is not just lower supplier overhead. We now have predictable costs, clearer reporting, and a partner who explains where investment will make the biggest operational difference."
Growing Australian Business