Planning a 3CX rollout: the pre-install checklist
A practical pre-install checklist for a smooth 3CX rollout — licences, numbers, internet, phones and staff training.
A 3CX rollout goes smoothly when the boring groundwork is done before anyone touches the system. Most go-live headaches — calls dropping, the wrong phone ringing, staff fumbling on day one — trace back to something that should have been sorted weeks earlier. This checklist covers what to nail down first, so cutover day is a quiet non-event rather than a fire drill.
You do not need to be technical to use it. Work through each section and you will either be ready to install or know exactly which bits to hand your installer.
Decide where 3CX will live (and lock the licence)
Settle two questions first: where the system runs and how it is licensed.
The 3CX phone system can run hosted in the cloud, self-hosted or on-premise. Each has trade-offs around cost, control and who keeps it patched — our guide on hosted, self-hosted or on-premise 3CX walks through the choice. For most SMEs we set up a hosted PBX so there is no on-site box to maintain.
For licensing, work out your concurrent call needs and which edition gives you the features you want — call queues, the Call Flow Designer, integrations and so on. We cover the editions in 3CX licensing explained. Get this right early, because it shapes what the rest of your build can do.
Sort your numbers and SIP trunk
Numbers and the trunk that carries calls are the part most likely to cause downtime if rushed.
List every number
you use — main lines, direct numbers, and any 1300 or 1800 numbers. You will map each to an Inbound Rule, so you need the full inventory now.
Plan the port.
Keeping existing numbers means porting them from your current carrier — done properly, with no loss of service. Our guide on porting numbers without downtime and our number porting page cover the timing.
Connect a SIP trunk.
3CX needs a SIP trunk to make and receive calls over the internet. If trunks are new to you, SIP trunks explained is a five-minute read.
Porting can take weeks depending on the losing carrier, so start early. Never schedule a port to complete on go-live day — give yourself a buffer.
Check your internet — it is the foundation
3CX is a VoIP system, so call quality lives and dies on your connection. A great phone system on a poor link still sounds bad. Each concurrent call needs roughly 100 kbps each way, so size your business internet for your busiest hour. Check upload as well as download — many plans are lopsided, and upload is what carries your voice.
Wired beats wireless
for desk phones. Plan cabling and switch ports for every handset.
Consider the connection type
business NBN, gigabit fibre or 5G fixed wireless all work; the right one depends on your site and headcount.
Plan for failure.
If your phones cannot go down, add internet failover so a dropped link does not silence your business.
If your firewall does Network Address Translation (NAT), it needs the right settings or you will hit one-way audio. A Session Border Controller (SBC) or correct STUN configuration handles this — flag it to whoever sets up the network.
Choose and prepare your phones
3CX is flexible about how people take calls, so decide per person what each one actually needs — a warehouse may share one desk phone, a sales team may run entirely on the apps.
Desk phones
Yealink, Fanvil and Snom are the common choices. They are provisioned automatically from the Admin Console rather than configured by hand; see provisioning desk phones for 3CX.
Apps
the Web Client runs in a browser, with desktop apps for Windows and Mac plus mobile apps for iOS and Android. Many staff need nothing more.
Headsets
sort these for anyone living on the phone or working from the apps.
Map your call flow on paper first
This is the step people skip and regret. Sketch how a call should move through your business before anyone builds it in the Admin Console:
Extensions
list every person and the extension number they will get.
Inbound Rules
decide where each incoming number lands: a person, a ring group, a call queue, or a digital receptionist (IVR).
Office Hours
define your business hours and what happens after them, on weekends and on public holidays.
Voicemail
decide who gets voicemail and turn on voicemail-to-email so messages land in the inbox.
Outbound Rules
confirm how outbound calls are routed and which trunk they use.
A one-page diagram saves hours of rework. If you want a queue rather than a simple ring group, pick a polling strategy now — Hunt (ring all), Round robin, Least talk time or Longest waiting each behave differently for your team.
Security, backups and training
Three things turn a working system into a dependable one:
Security.
A phone system on the internet is a target for toll fraud. Set anti-fraud and outbound spend limits, and restrict international calling — see securing 3CX against toll fraud.
Backups.
Configure Backup & Restore with a schedule from day one, so a rebuild is minutes, not days.
Training.
Give staff 20 minutes on transferring calls, parking, voicemail and the apps before go-live — the cheapest thing you can do to make the rollout feel smooth.
None of this is hard, but it is a lot to coordinate. If you would rather hand the whole rollout to a local team, SIP Connect plans, installs and supports 3CX for Melbourne and Australian businesses — call 1300 747 266 or grab a free bill review.
What we see installing this in Melbourne
The thing that bites Melbourne SMEs most often is not 3CX itself — it is the connection underneath it. We still walk into offices on a cheap residential-grade NBN plan with 20 Mbps upload shared across thirty staff, and a consumer router with SIP ALG quietly mangling registrations. Before a rollout we test on the actual office link at the actual busy hour, not on a spec sheet.
Porting is the other one. Losing carriers in Australia routinely take two to four weeks, and complex accounts with a mixed bag of direct numbers and 1300s take longer. We never schedule a port to complete on cutover day — there is always a buffer, and the new system is live and tested first.
Where we add the most value is the week after go-live: sitting with reception, fixing the call flow nobody mentioned in planning, and walking staff through the mobile app so they actually use it.
Frequently asked questions
How long does a 3CX rollout take to plan?
The build is quick, but number porting is the long pole — allow two to four weeks. Internet upgrades, if needed, can take longer. Start the port and any connection changes early and the rest falls into place.
Do I need new phones to move to 3CX?
Not necessarily. Many staff run entirely on the Web Client or the desktop and mobile apps. If you want desk phones, handsets from Yealink, Fanvil and Snom provision automatically, and some existing SIP handsets can be reused — worth checking before you buy.
Will porting my numbers cause downtime?
Done properly, no. The new system is built and tested first, and the port is scheduled to complete cleanly. The risk comes from rushing — never aim to port and go live on the same day. See porting without downtime.
What internet speed do I need for 3CX?
Budget roughly 100 kbps each way per simultaneous call, sized for your busiest hour, and remember upload matters as much as download. If phones are business-critical, add failover.
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