In short: A hosted PBX, also called a cloud PBX, is a private branch exchange run by a provider in a data centre rather than on your premises. It handles extensions, transfers, groups, menus and voicemail as before, while the provider looks after the hardware, software updates, security patching and connection to the phone network.
What a PBX does
A PBX (private branch exchange) is the switch at the centre of a business phone system. It lets you share a set of outside lines and numbers between many users, and it provides the features people take for granted:
- Internal extensions and free calls between them
- Transfers, call park and call pickup
- Hunt groups, ring groups and call queues
- Auto attendant menus and time-of-day routing
- Voicemail, music on hold and call logging
For definitions of these and other terms, see our phone system features glossary.
Hosted PBX vs a PBX on site
With an on-site PBX, the box, its software and its line cards live in your building, and you (or your maintainer) look after them. A hosted PBX provides the same switching from a data centre. Phones and apps connect to it over the internet using VoIP, and the provider connects it to the public network over SIP.
| PBX on site | Hosted PBX | |
|---|---|---|
| Where it runs | Your comms room | The provider's data centre |
| Lines | Analogue, ISDN or SIP trunks into the box | Included in the service over the internet |
| Updates and patching | Your maintainer, often on a visit | The provider, centrally |
| Adding sites and home workers | Extra hardware, VPNs or licences | Phones and apps register from anywhere |
| If the building is out of action | Calls usually stop | Calls can divert to other sites, mobiles or apps |
This page explains the hosted model. For a full side-by-side comparison, including cost profile and when on-site still makes sense, read hosted vs on-premise phone systems.
What moves to the provider, and what stays with you
Moving to a hosted PBX changes who is responsible for what. Being clear about it up front avoids surprises.
The provider takes on:
- The PBX hardware or virtual servers, and their power, cooling and resilience
- Software updates and security patching of the platform
- Connection to the public phone network, numbers and emergency call routing
- Monitoring and capacity on the platform side
You keep responsibility for:
- Your internet connection and office network, including QoS and firewall settings
- Handsets, headsets and the devices people use for apps
- Power to routers, switches and phones on site, including any UPS
- Who has admin access, and your own policies on call recording and retention
Forever Systems can take on much of your side too: we check connectivity, supply and provision handsets, and support moves, adds and changes.
How to move your existing PBX features across
Most of what your current PBX does can be rebuilt on a hosted platform, often more simply. A typical migration looks like this:
- Export what you have. Extension list, DDI numbers, hunt groups, call queues, auto attendant menus, opening hours and voicemail boxes.
- Find the hidden lines. Fax, door entry, lift and alarm lines, card terminals and franking machines that use the old system or analogue lines.
- Decide what to keep. Tidy up unused extensions and groups, and confirm the menu callers should hear.
- Choose the platform. Match your needs to Forever UC, hosted 3CX, Webex Calling or Microsoft Teams Phone.
- Rebuild and test. Configure extensions, groups and menus, then test every route before go-live.
- Port numbers. Move your numbers on an agreed date, with diverts in place. See number porting.
- Switch over and train. Deploy handsets and apps, train reception and admins, then decommission the old PBX.
Analogue devices can often stay through an analogue telephone adapter. Our ISDN replacement options page covers the wider choice if your PBX is on ISDN today.
Is a hosted PBX right for you?
A hosted PBX tends to suit organisations that:
- Have an ageing PBX that is out of support or due a costly upgrade
- Are on ISDN or analogue lines and need to move before 31 January 2027
- Have home workers, several sites or plans to grow
- Would rather not manage phone system hardware
If your current PBX is modern, supported and does what you need, keeping it on SIP trunks may be better value. 3CX is one platform that can run either way, hosted or on your own servers. Contact us and we will give you an honest view of both.
Why choose your cloud phone system with Forever Systems
We are vendor-neutral. Forever Group supplies and supports several cloud phone platforms, so we recommend the one that fits how your organisation works rather than the one we happen to sell.
- Side-by-side comparison of hosted 3CX, Microsoft Teams Phone, Forever UC, Forever Teams and Webex Calling for your users
- Contact centre and call recording options matched to your call volumes and CRM
- Number porting, handsets and set-up handled for you, including the move off analogue and ISDN lines
- Connectivity checked so call quality is right from day one
- UK support for moves, adds, changes and faults
- For BT Cloud Voice, see our BT Business Partner site cloudvoice.cloud
We work with businesses, schools, charities and public sector organisations. We do not sell consumer phone services.
Want a vendor-neutral cloud phone system comparison and quote?
Tell Forever Systems what you need and we will come back to you by email with options, not a hard sell.
Contact usFrequently asked questions
What is the difference between a hosted PBX and a cloud PBX?
In everyday use, nothing. Both mean a PBX that runs in a provider's data centre rather than on your premises. Providers use the terms interchangeably.
Can I keep my desk phones with a hosted PBX?
Sometimes. Many SIP desk phones can be re-provisioned for a hosted platform if they are supported. Older digital or proprietary handsets usually cannot, and are replaced with IP phones, cordless DECT phones or apps.
What happens to my PBX features when I move to a hosted PBX?
Extensions, hunt groups, queues, menus, voicemail and opening hours are rebuilt on the hosted platform. We map them from your current system first, so callers hear the same menu and calls reach the same people.
Is a hosted PBX secure?
The provider patches and monitors the platform centrally, which removes one common risk: an unpatched PBX on site. You should still use strong admin passwords, multi-factor authentication where offered, and controls on international calling.