VoIP for NZ Businesses

For your business, the practical questions are whether the connection can support clear calls, which existing devices will work, and what happens when the internet or power fails. This guide answers those questions.

Looking for setup and support? See our business phone systems service. Comparing hosted options? Read our cloud phone systems guide.

What is VoIP and how does it work?

VoIP turns speech into small data packets, sends them across an IP network, and turns them back into sound at the other end, in real time. For the person on the call, it works like any other phone call, from a desk phone, a computer app or a mobile app.

It helps to separate the parts. VoIP carries the call. The phone system handles extensions, menus, queues and other features. That system can run in the cloud or at your premises. A SIP trunk connects a compatible phone system to the telephone network, so calls can reach ordinary landline and mobile numbers.

How is VoIP different from a traditional phone line?

A traditional analogue line is a copper circuit from your premises to the exchange, carrying one call at a time. An internet calling service carries calls as data over your internet connection, so one connection can carry several calls at once, subject to its capacity.

A single phone line is not the same as a traditional PBX. Older PBXs could already provide queues, auto-attendants and call recording, so those features did not arrive with internet calling. What it changes is how calls travel, and that makes it easier to use apps, reach staff away from the office and connect to other business systems.

Chorus is retiring its copper network, and the timing depends on where you are. Check your address on the Chorus copper withdrawal map rather than assuming one date applies to every business.

Is VoIP the same as a cloud phone system?

No. VoIP is not inherently cloud-hosted, per-user priced or maintenance-free. A cloud phone system runs the phone platform in a provider’s hosted environment. An on-site IP phone system runs it on equipment at your premises. Both carry calls this way, and a SIP trunk can connect either one to the telephone network.

A SIP trunk can also let a business keep a recent, supported on-site phone system while replacing the lines that feed it. Which option suits depends on the system you have, its supported life and condition, and how your staff work. Our cloud phone systems guide covers the hosted choice in detail.

Whichever model you choose, some equipment stays local. Routers, switches, handsets, headsets, computers and power equipment still need looking after, and should be replaced based on vendor support and condition rather than a fixed age.

What equipment and connection do you need?

You need a phone service, devices and a network that can carry voice reliably. Devices can be desk phones, computer apps, mobile apps or a mix, with headsets for staff who spend a lot of time on calls.

Size the connection for the number of calls that can happen at the same time. Allow roughly 100 kbit/s per call in each direction as an indicative figure, which varies with the codec and overhead, and keep headroom for everything else the business uses. Better still, ask the provider to size it for your expected simultaneous calls.

Speed is only part of it. Voice is sensitive to packet loss, latency and jitter, so a connection that handles email and video well can still produce choppy calls. Quality of service settings help manage congestion on the parts of the network you control, but they cannot fix every problem upstream. Carriers, devices, Wi-Fi coverage and remote workers’ home connections can all affect a call too.

Before switching, test the network against the selected service’s requirements under normal business load. Our guides to business internet and network cabling cover the connection and the wiring behind it.

What does VoIP cost?

There is no single price, because it is the technology rather than the product. Some services charge per user, while others price the system by how many calls can happen at the same time. Compare setup, licences, calling allowances, extra destinations, devices, network work, support and contract terms, and do not assume features or calling are bundled or that savings follow automatically.

Our cloud phone systems guide has a fuller cost checklist, and our business phone systems page explains how Exodesk scopes and quotes a phone project.

What happens during an outage?

Plan for three different events, because each stops different things.

• Office internet outage. If the office connection fails, mobile apps may keep working over cellular data, provided the hosted phone service remains available.
• Power cut. A power outage can also stop the fibre ONT, router, switches and desk phones. Agree which equipment needs backup power.
• Provider outage. Decide how calls will be routed if the phone provider itself is unavailable.

Test the fallback before you rely on it; an active call may drop during a changeover. Mobile apps, call forwarding and a second internet connection are not included in every service, so ask who configures each option, whether it costs extra and which failures it actually covers.

Agree how staff can call 111 during an outage, and confirm emergency calling arrangements for each site and app with the provider. The Commerce Commission’s 111 Contact Code protects residential landline customers, not businesses, so this is yours to plan. Our business continuity plan guide covers how to decide which services need a fallback.

How is VoIP secured?

Internet calling sits on the same network as the rest of your business systems, so it needs similar protection. The main risks are toll fraud, where someone gains access and runs up call charges, interception of unencrypted traffic, attacks that overload the service, and phishing that targets voicemail sent to email.

• Admin access. Use multi-factor authentication for supported administrative access and strong, unique credentials everywhere else.
• Calling restrictions. Restrict calling destinations where appropriate and monitor unusual usage.
• Encryption. TLS protects SIP signalling, which sets up and ends calls. SRTP protects the audio itself. Confirm which connections support each and enable them where supported.
• Updates. Keep the phone system and connected devices updated.

Encryption on one connection does not mean the call is protected end to end once it reaches the public telephone network, and support varies by device and carrier. Ask what is configured and supported for your service rather than judging security from the price. Phone security belongs in your wider cyber security planning.

What should you check before switching?

Timing depends on the numbers, sites, devices, network work and provider dates involved, so agree it after these checks rather than working to a standard figure.

• List numbers and connected services, including alarms, lift phones, fax, door entry and EFTPOS.
• Check contracts for end dates and exit charges on the current phone and broadband services.
• Test the network against the selected service’s requirements under normal load.
• Choose devices and confirm which existing handsets and headsets will work.
• Design call flows for business hours, after hours, groups, queues and voicemail.
• Confirm 111 arrangements for each site and app.
• Agree the porting date, an outage window and a fallback way to receive calls.
• Test after cutover: incoming calls, outgoing caller ID, transfers, queues and after-hours routing.

If you run a busy sales or support line, contact centre software adds routing, wallboards and wait-time reporting on top of the phone system.