Business Phone Systems Sydney | VoIP, 3CX & Teams Phone

Key facts

• Modern business phone systems run over the internet (VoIP), so they replace fixed phone lines and on-site PBX hardware.
• The two common paths for a Sydney SME are a hosted VoIP platform such as 3CX, or Microsoft Teams Phone for businesses already on Microsoft 365.
• 3CX licenses by simultaneous calls rather than per user, which often costs less for teams where not everyone is on the phone at once.
• Any VoIP system needs SIP trunks (the connection to the public phone network) and a business-grade internet connection to run well.
• Existing Australian numbers, including local, 1300, and 1800 numbers, can be ported across, usually in 10 to 20 business days.

What is a business phone system in 2026?

A business phone system today is almost always a VoIP system, meaning calls travel over your internet connection instead of a traditional phone line. The old model of a physical PBX box in a comms cupboard, wired to copper lines from a carrier, is being retired as Australia’s legacy phone network winds down. What replaces it is software: a cloud or server-based platform that handles calls, voicemail, call queues, and auto-attendants, reached from a desk phone, a computer, or a mobile app.That shift matters because it changes what you are buying. Instead of hardware plus line rental, you are buying a software licence plus a connection to the phone network (a SIP trunk) plus, usually, someone to run it. The upside is flexibility: staff get the same business number whether they are in the office, at home, or on their mobile, and adding or moving an extension is a config change rather than a cabling job.

3CX or Microsoft Teams Phone: which suits your business?

The right platform depends mostly on how your business already works. Microsoft Teams Phone is the natural fit if you are already running on Microsoft 365 and your staff live in Teams all day, because it adds calling to an app they already use. 3CX is the stronger fit when you want a dedicated phone platform with richer call-handling, reception and queue features, multi-site support, or tighter control over call costs.We deploy and support both, and we have no reason to push one over the other beyond what suits the business in front of us. 3CX’s simultaneous-call licensing tends to win for businesses with a lot of staff but fewer concurrent calls, like a team where everyone has a phone but only a handful are ever on a call at once. Teams Phone tends to win on simplicity for Microsoft-365-centric offices. We walk through the trade-offs in detail in our guide to 3CX vs Microsoft Teams Phone, and you can read the specifics of each on our 3CX phone system and Microsoft Teams Phone pages.

What does a business phone system cost for a Sydney SME?

A VoIP business phone system has three cost layers: the platform licence, the SIP trunk and call charges, and the management. For 3CX, the licence is annual and priced by simultaneous calls and edition rather than per user. For Teams Phone, the calling licence starts at roughly AU$13 per user per month ex GST, or around AU$22 all-inclusive with an Australian number and calling plan. On top of either, SIP trunks for an SMB typically run from about AU$15 to AU$60 per month depending on numbers and call volume.The honest answer to “what will it cost us” is that it depends on your headcount, how many calls you handle at once, and which platform fits, so we scope it against your actual usage rather than quoting a headline number. Advisory and project work is charged at AU$165 per hour ex GST, and most ongoing management is bundled into a per-user or per-system monthly agreement.

Can we keep our existing phone numbers and handsets?

Yes to the numbers, usually yes to the handsets. Australian numbers, including geographic, 1300, and 1800 numbers, port across to a new VoIP system, with the process typically taking 10 to 20 business days through the losing carrier. We manage the port so your numbers keep working right up to the cutover.Handsets depend on what you have. Many modern IP desk phones can be reconfigured for a new platform, while older or proprietary handsets tied to a legacy PBX usually cannot and are replaced with VoIP-capable models. We audit what you have during scoping and tell you honestly what can be reused, because there is no point buying new hardware you do not need.