VoIP Phone System for Business | AMVIA Guide 2025

Most UK SMEs are now moving off legacy phone lines because the old copper network is being switched off. Openreach is retiring the traditional analogue and ISDN network and migrating customers to digital voice services (Openreach: the big switch off). If you run a business phone estate, replacing it with a hosted business VoIP system is no longer optional — it is the default. This guide covers how it works, what it costs, which providers lead the UK market, and how to migrate without dropping a single call.

What is a business VoIP phone system?

A business VoIP phone system is cloud telephony where the PBX — the software that answers and routes calls — runs in the provider's data centre, not on a box in your server room. Staff make and receive calls on IP desk phones, laptop softphones or mobile apps, all connected over the internet.

Because there is no on-premise hardware to maintain, you manage everything through a browser portal: extensions, call routing, voicemail greetings, hunt groups and reporting. Ofcom confirms VoIP and managed digital voice are now the standard replacement for the retiring PSTN (Ofcom: the future of fixed telephone services).

• No on-site PBX — the call platform lives in the cloud, fully managed
• Any device — desk phone, desktop app or smartphone, same number everywhere
• Browser admin — moves, adds and changes take minutes, not an engineer visit
• Built for hybrid work — staff keep their extension at home, on site or on the road

How does a business VoIP phone system work?

Inbound calls from external numbers arrive at the cloud PBX, which applies your rules: send them to an auto-attendant, ring a hunt group, route to a named extension, or drop to voicemail. Outbound calls travel from your handset or app over the internet to the provider, then onto the public network.

Each user connects through one of three endpoint types. The choice affects cost — softphone apps remove the need to buy hardware at all.

• IP desk phones — physical handsets that register to the cloud PBX
• Desktop softphones — calling from a laptop using the business number
• Mobile apps (iOS and Android) — full functionality from a smartphone

The system depends on a stable internet connection, which is why connectivity and voice should be designed together. Many AMVIA clients pair VoIP with a business leased line for guaranteed, symmetrical bandwidth that protects call quality at peak times.

What features should a business VoIP system include?

A capable business VoIP platform covers four areas: call management, analytics, mobility and integrations. Treat anything missing from this list as a gap, not a saving. The features below are what separate a professional phone system from a consumer calling app.

Call management

• Auto-attendant — answers professionally and routes on caller input
• Hunt groups — spreads calls across a team to cut missed calls
• Call recording — for compliance, training and quality review
• Call transfer and park — clean internal handling between extensions
• Conference calling — multi-party calls run from the platform

Analytics, mobility and integrations

• Real-time dashboards and historical reports on volumes, answer rates and queue waits
• Mobile and desktop apps so the business number follows the user anywhere
• CRM integration (Salesforce, HubSpot, Dynamics) with screen-popping and call logging
• Microsoft 365 integration — calendar, contacts and Microsoft Teams calling for firms already on M365

How much does a business VoIP phone system cost?

UK hosted VoIP is priced per user per month, usually in three tiers. Entry plans cover core calling; mid plans add recording, analytics and CRM links; enterprise plans add contact-centre and AI features. Expect pricing from £5.95 per user per month for most SMEs, plus optional hardware.

IP desk phones cost roughly £80–£200 per device (typical UK 2026 range) if you want physical handsets. Many businesses skip that entirely and run softphone and mobile apps, removing hardware from the project cost altogether.

Which VoIP provider is best for UK business?

There is no single best provider — the right choice depends on whether you prioritise managed reliability, value, Microsoft 365 integration or contact-centre depth. Below are five platforms AMVIA works with for UK SMEs, with indicative pricing. We deploy the one that fits your stack, not the one with the biggest margin.

For Microsoft-centric firms, putting calling inside Teams avoids a second app entirely — see our guide to hosted phone systems and how SIP trunking connects an existing PBX to the cloud.

How do you migrate a business to VoIP?

A clean VoIP migration follows a fixed sequence and takes most SMEs one to three weeks. The single biggest variable is number porting, which runs in parallel with platform build so it rarely extends the overall timeline. Skipping the audit step is where migrations go wrong.

1. Audit every existing line and voice dependency — including alarm, lift and fax lines 2. Confirm your internet connection can carry voice reliably 3. Select and configure the VoIP platform and call routing 4. Port existing numbers (around 5–10 working days) 5. Provision endpoints — desk phones, desktop or mobile apps 6. Train staff and run go-live testing

AMVIA manages this end to end, so nothing is missed and your lines stay live throughout the cutover. Because we are a security-first provider, we also harden the platform — see VoIP security — and plan around the PSTN switch-off timeline rather than leaving it to the last minute.