3CX is a software-based business phone system that you licence per system rather than per user, run on your own server or have hosted for you, and connect to the public phone network through a SIP trunk you choose yourself. That last part is the whole argument. Most business phone systems sold in Australia bundle the phone system and the phone calls into one per-user monthly fee from one supplier. 3CX separates them.
Whether that separation is worth having depends on how many users you have, how much call flow complexity you need, and whether anyone in your business wants to own a decision instead of accepting a bundle.
How the licensing model actually works
This is the part people get wrong, so take it slowly.
3CX is licensed per system, per year, based on simultaneous calls. A simultaneous call is one call happening at one moment, and 3CX counts internal calls as well as external ones. It is not a per-user, per-month subscription. Adding a staff member does not add a line item. Adding enough staff that more people are on the phone at once does.
There are four editions: 3CX SMB Free, 3CX Basic, 3CX PRO and 3CX AI. SMB Free is free for up to 10 users and includes hosting, and you can create up to three free subscriptions on an account. The three commercial editions are priced on the number of simultaneous calls you need, and each simultaneous call tier carries a maximum number of users and extensions. Feature differences between Basic, PRO and AI are what you would expect: the higher editions add contact centre, integration and AI capability.
We are not quoting prices here, because 3CX changes them, runs promotions and prices in a foreign currency. Get a current quote. What we will say is that the shape of the model is the point: the cost curve flattens as headcount grows, which is why 3CX suits a business with a lot of extensions and modest concurrency, and suits a call centre far less well proportionally.
The annual subscription covers more than the licence key. It includes PBX updates and service packs, security updates, the 3CX fully qualified domain name service, automatic renewal of the Let’s Encrypt SSL certificate, IP phone firmware and provisioning template updates, CRM connector updates, VoIP provider template updates, the iOS and Android apps, video conferencing and live chat. If you self-host and let the subscription lapse, you stop receiving security updates on an internet-facing server. Do not do that.
3CX sells through partners rather than direct.
Self-hosted, hosted by 3CX, or on-premises
Three deployment choices, and they are genuinely different commitments.
On-premises means a server in your comms room. It made sense when the alternative was expensive bandwidth. Today it mostly makes sense for sites with poor or expensive internet where you want internal calls to keep working when the link drops, and for businesses with an existing virtualisation platform and someone competent running it. The trade-off is that your phone system now depends on your power, your UPS and your air conditioning.
Self-hosted in the cloud means you run 3CX on a virtual machine you control. 3CX supports Windows or Linux, on AWS, DigitalOcean, Azure or Google. You get full control, you can put the instance in an Australian region for latency and data residency, and you own the patching, the firewall rules and the backups. This is the option we most often recommend for businesses with real complexity, and it is the one that most needs a competent provider behind it, because an unmanaged internet-facing PBX is a target.
Hosted by 3CX means 3CX runs the instance. There is an annual hosting service charge based on your simultaneous call count, on top of the edition licence, and hosting is included at no charge for SMB Free and for the duration of a trial. It is the lowest-effort option and the right default for a small business that wants the licensing model without the server responsibility. The trade-off is less control over where the instance sits and what version it runs.
SIP trunk choice matters more than the PBX choice
3CX does not sell you phone calls. You bring your own SIP trunk, which in Australia means choosing a carriage service provider and, in practice, choosing whether your voice quality is good.
What to actually check when selecting a trunk:
- Australian network, Australian numbers. Geographic numbers in the right rate zone, and the ability to hold your existing numbering.
- Channel count versus your simultaneous call licence. These are separate limits and both bite. Ten SIP channels behind a four simultaneous call licence wastes money in one direction, and the reverse strands calls.
- Emergency calling. Calls to Triple Zero must be carried, and the address the emergency service organisation receives is the service address recorded in the Integrated Public Number Database. With softphones on laptops this becomes a genuine safety question rather than a compliance box, because the registered address is not where the person is. Decide in advance how mobile and remote workers reach emergency services, and tell your staff.
- Codec and transcoding policy. G.711 costs bandwidth and sounds fine. G.729 saves bandwidth and does not. Know which you are getting.
- Redundancy. A second trunk from a second provider, or at minimum a failover destination for inbound numbers when the PBX is unreachable.
- Whether the provider has a 3CX template. 3CX ships pre-configured templates for supported providers. Using one removes an entire category of tedious fault.
The other half of call quality is not the trunk at all. It is your network: the firewall, whether SIP ALG is switched on and quietly mangling your signalling (turn it off), whether you have QoS on the LAN, and the quality of your internet connection. We have resolved far more voice quality complaints by fixing a router than by changing carrier. How VoIP works for Australian businesses covers the underlying mechanics.
Number porting is a process, not a setting
Porting your existing numbers to a new provider is governed by industry codes registered with the ACMA: Local Number Portability C540:2023 for fixed geographic numbers, Mobile Number Portability C570:2024 for mobiles, and Inbound Number Portability C657:2024 for 13, 1300 and 1800 services.
Three practical points.
A simple port is a single number with no associated services and it moves quickly. A complex port is anything with multiple numbers, a number range, or a service attached, and it takes longer and involves a scheduled cutover. Most business ports with a number block are complex. Plan for a date, not for a moment.
Do not cancel the old service. Cancelling a service before the port completes strands the number, and recovering it ranges from painful to impossible. Cancellation happens automatically as part of the port.
Your billing account details must match exactly. Ports fail on the account name being an abbreviation, or on a trading name where the losing carrier holds a company name. Get a copy of the current bill before you lodge anything.
Apps, handsets and how people will actually use it
Users get a web client, a Windows app, and iOS and Android apps included in the subscription. In our experience the split in a 20 to 100 person business is roughly that reception and anyone customer-facing wants a physical handset, everyone else lives in the app, and a handful of people want both.
3CX auto-provisions supported IP phones and maintains firmware and provisioning templates as part of the subscription, which is the practical reason to buy handsets from the supported list rather than whatever is cheapest. An unsupported handset works until a firmware update, and then it is your problem.
Call flows and queues are where the value is
If you only need extension-to-extension calling and a voicemail box, almost any system will do and this decision does not matter.
3CX earns its place when the call flow is a real business process. Digital receptionist menus, ring groups, call queues with defined strategies and wait announcements, office hours and holiday routing, and a call flow designer for logic that goes beyond a menu. Queues in particular are where a hosted carrier PBX starts charging per agent and 3CX does not.
Reporting is the other half. If you are running a service desk, a bookings line or a sales team, call statistics that tell you abandonment rate and time to answer are worth more than the phone system itself.
CRM integration, and the Microsoft and Google question
3CX ships connectors for common CRM platforms, giving click to dial, screen pop on inbound calls with the matched contact, and call journalling back into the CRM record. It also integrates with Microsoft 365 and Google Workspace for user directory sync and calendar-based presence, which matters in a mixed Windows, Mac and Google environment where you do not want to maintain a second user directory by hand.
There is a Microsoft Teams integration, which routes calls between 3CX and Teams. It works, and it is a sensible answer when part of the business lives in Teams and part needs proper call handling. It is not the same as Teams Phone, and choosing between them is a real decision rather than a formality.
Where 3CX genuinely beats a carrier-provided hosted PBX
Four situations, and they are narrower than most 3CX resellers will tell you.
You have many extensions and modest concurrency. A warehouse, a school, a clinic with a phone in every consulting room, a hospitality venue. Per-user pricing punishes you for handsets that ring twice a day. Per-simultaneous-call pricing does not.
You want to keep your carrier separate from your phone system. If a carrier disappoints you, you change the trunk, not the phone system. If your phone system disappoints you, you keep your numbers. Bundled hosted PBX makes both changes into the same painful project.
Your call flows are genuinely complex and your current provider charges for every change. Owning the system means changes happen when you need them.
You need the system to sit inside your own environment for latency, data residency or integration reasons.
When 3CX is the wrong answer
Say this part out loud before you sign anything.
You are all-in on Microsoft and you value one bill and one support path. Teams Phone with a direct routing or calling plan arrangement is a legitimate and often better answer for a business that already lives in Teams. Comparing them properly is worth an hour: hosted PBX, Teams Phone or 3CX does exactly that.
You have fewer than ten users, simple needs, and nobody to manage anything. A carrier hosted PBX bundled with your mobiles is less to think about, and the licensing advantage of 3CX has not kicked in yet.
You are a real contact centre. 3CX has queues, reporting and contact centre features, and for a team of eight taking calls it is more than adequate. If you need workforce management, quality assurance scoring, omnichannel routing across voice, chat, email and social with unified reporting, and outbound dialler compliance, you want a dedicated contact centre platform.
Nobody will own it. Self-hosted 3CX is an internet-facing server. It needs patching, firewall management, certificate renewal, backup and monitoring. If you are not going to do that and you are not going to pay someone to do it, take the hosted option or take a carrier service.
You have a genuinely bad internet connection and no fallback. Fix that first.
Why we mention the TCP Code
TechAssist complies with the Telecommunications Consumer Protections Code and is a member of the Telecommunications Industry Ombudsman scheme, which is unusual for a managed service provider and which you can check yourself in the TIO’s public register of members. Most MSPs that sell you phones are reselling someone else’s service under a referral arrangement, which means the consumer protections attach to a supplier you have no relationship with.
The code registered with the ACMA is C628:2019, incorporating Variation No.1/2022. It is worth knowing that this is changing: on 27 March 2026 the ACMA announced it will determine an enforceable industry standard under section 125 of the Telecommunications Act 1997 to replace the industry-developed code, and stated that the existing 2019 TCP Code remains in force until the new standard commences, at which point the code ceases to be registered. The obligations are not going away. They are moving into direct regulation with stronger enforcement.
What that means for you as a buyer is covered in what the TCP Code means when your IT provider sells you phones. The short version: ask whoever is selling you a phone system whether they are the supplier of the carriage service or an introducer, and get the answer in writing.
If you want a straight comparison of 3CX against a carrier hosted PBX and Teams Phone for your actual call volumes and headcount, we will do the numbers and tell you if 3CX is the wrong fit. Call 1300 028 324 or book a phone system review at https://techassist.au/contact/.
