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VoIP guide

What is VoIP? A guide for UK businesses

VoIP means making phone calls over an internet connection instead of a traditional phone line. Here is how it works, what you need, and what to ask before you choose a system.

By the Alltone Telecoms team. Updated 24 October 2026. About 2 minutes to read.

How VoIP works

VoIP (Voice over Internet Protocol) turns your voice into small data packets and sends them across the internet. A provider connects those calls to the normal phone network, so you can still call and be called by any landline or mobile.

With a hosted or cloud VoIP system, the phone system itself lives in the provider's data centre. Your users sign in from desk phones, computer apps or mobile apps, wherever they are.

What you need

  • A reliable internet connection: about 100 kbps each way per call with the G.711 codec
  • A business router, ideally with voice prioritisation (QoS)
  • Devices: desk phones, headsets, or just the apps
  • A provider to host your numbers and system

Why businesses switch

  • One system for office, home and mobile working
  • Add or remove users in minutes
  • Features like call recording, queues and reporting included
  • Keep your numbers wherever you move
  • No copper lines to lose in the PSTN switch-off

Questions to ask a provider

  • Where are your data centres and support team?
  • What is included per user, and what costs extra?
  • How long is the contract, and what happens at renewal?
  • How do you handle number porting?
  • What happens to calls if our internet fails?

Common questions

Something else on your mind? Call 020 7112 8558 or send us a message and a telecoms specialist will reply.

Is VoIP call quality as good as a landline?

On a decent connection, yes. HD voice codecs can sound clearer than traditional lines. Most quality problems come from Wi-Fi or congested connections, which a line test usually spots.

Can I use VoIP on my mobile?

Yes. Mobile apps let staff make and take calls using the business number on their own phone.

Talk to a telecoms specialist

Tell us how your business takes calls today and we will recommend a setup, with a clear monthly price. Most quotes are ready the same day.

  • UK-based support team
  • Free setup and number porting on most plans
  • Monthly rolling options available
  • No obligation quote

Prefer to talk? Call 020 7112 8558, Monday to Friday, 9am to 5.30pm.

Get a quote

Tell us a little about your business. We reply within one working day, and there is no obligation.

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