A traditional office PBX carries calls. If you're on one, you pay line rental, call charges and a maintenance contract for hardware that lives on-site. Adding a line means an engineer visit. Voice over Internet Protocol (VoIP) uses your internet connection instead. The platform runs in the cloud. You change settings from a browser. Extra people are a licence.
How VoIP differs from traditional telephony
A traditional PBX sends traffic across dedicated ISDN or analogue circuits. The switchboard sits in your building. Upkeep is expensive. Capacity changes involve a site visit.
VoIP carries the same voice traffic across the internet. The platform is hosted remotely. You add or remove users in an admin portal. Headcount changes are a licence adjustment.
The business case for VoIP
Lower costs
Line rental on a traditional system is usually £15 to £25 per user per month, before call charges, maintenance contracts and hardware depreciation. Microsoft Teams Phone or a hosted PBX is usually £8 to £15 per user per month, with UK calls included.
Calls away from the desk
VoIP works on desk phones, laptops and mobiles. Staff keep the business number and can place or take calls from any location with a working internet connection. Hybrid and remote teams rely on that.
Administration
Adding a user, changing a routing rule or setting up an auto-attendant takes minutes in a portal. It does not need an engineer on site.
Features that used to cost extra
Call recording, voicemail delivered to email, auto-attendants, call queues, call analytics and CRM integration are included as standard. On a traditional system each of those is usually a paid add-on.
What you need before switching
Stable internet. Each concurrent call uses about 100Kbps. Twenty simultaneous calls need at least 2Mbps of dedicated upstream bandwidth. A leased line or a well-specified FTTP circuit is the usual recommendation.
Voice given priority. Your router or firewall needs Quality of Service (QoS) rules so voice traffic is treated ahead of general internet use. Without that, a large file download will make calls sound poor or drop.
Power and backup. Traditional phones keep working through a power cut. VoIP doesn't, unless a UPS (battery backup) covers the router and the switches. Plan for it.
The ISDN switch-off
BT is closing the PSTN and ISDN networks by January 2027. Businesses on those lines have to move to VoIP before that date. An earlier start leaves time to plan the cutover.
Microsoft Teams Phone vs hosted PBX
Teams Phone suits a business that already uses Microsoft 365. External calls sit in the same application as chat, video meetings and files. For most SMEs, it's the simpler route.
A hosted PBX suits businesses that need heavier telephony, including layered call routing, wallboards and contact centre functions.
Where automation fits
Routine questions arrive by phone. Invoice copies and password resets consume the queue. An AI helpdesk can answer those and pass on anything that needs a person.
What Wanzo handles
We plan, install and run business VoIP for UK companies. We check your connectivity, set QoS on the network and move you off the existing system. Your numbers stay in place. The cutover is handled so the phone service does not go down.
Next step
Send an enquiry with a note on how your team takes calls today. We'll set out a monthly plan covering the phone service and the network it runs on.