In short: A cloud phone system is a business phone system (PBX) run by a provider in a data centre instead of on your premises. Calls travel over the internet using VoIP to desk phones, softphones and mobile apps, and the provider connects them to the public phone network. You need a good internet connection, a voice-friendly network and devices.
A plain-English definition
Every business phone system does the same basic jobs: it gives people extensions, routes incoming calls to the right person or group, plays greetings and menus, and connects calls to the outside world. Traditionally that work was done by a PBX (private branch exchange), a box in a comms cupboard wired to phone lines from the exchange.
In a cloud phone system, the PBX is software running in the provider's data centre. Nothing sits in your building apart from the internet connection and the devices people use. You manage users, numbers and call flows from a web portal, and the provider looks after the servers, updates and security patching. That is why you will also hear it called a hosted phone system, a hosted PBX or hosted VoIP.
How a cloud phone system works
Behind the scenes, three things happen on every call:
- Your device registers with the cloud PBX. A desk phone, softphone or mobile app connects over the internet and tells the phone system it is ready to take calls for an extension.
- The PBX decides where calls go. When someone rings your number, the call arrives at the provider, and the phone system applies your rules: an auto attendant menu, a hunt group, a call queue, opening hours, voicemail.
- The provider connects you to the phone network. Calls to and from ordinary landlines and mobiles pass between the provider's platform and the public phone network (PSTN), usually over SIP trunks the provider runs for you.
The voice itself travels as data packets using voice over IP (VoIP). A codec compresses the audio, and your network should give voice priority so that delays and gaps are kept to a minimum. Our hosted VoIP page covers the technical side in more depth.
Numbers, call routing and the phone network
Your phone numbers are held by the provider (or ported to them from your old one) and pointed at the cloud PBX. Because numbers are no longer tied to a physical line in a building, a single number can ring a desk phone in one office, an app on a laptop at home and a mobile at the same time.
Call routing is set in software: you can add a holiday message, change a menu or move a user between groups in minutes. Most providers also offer direct dial (DDI) numbers for individuals, a choice of caller ID, voicemail to email, call recording and reporting. The phone system features glossary explains each term.
Microsoft Teams works in a similar way: Microsoft Teams Phone adds the PBX features, and a Calling Plan, Operator Connect or Direct Routing provides the connection to the phone network.
What you need to run one
- A reliable internet connection with enough upload as well as download capacity for your busiest hour of calls; business broadband or a leased line is best
- A network that prioritises voice, using quality of service (QoS) and often a separate voice VLAN, so large downloads do not break up calls
- Firewall settings that suit VoIP; features such as SIP ALG on some routers can interfere and may need turning off
- Devices: IP desk phones, cordless DECT handsets, headsets, or softphone apps for laptops and mobiles; see VoIP phones
- Power for your network: routers, switches and Power over Ethernet (PoE) phones need power to keep working
- A correct emergency address registered for each number or user, so 999 and 112 calls give the right location
Advantages and limits
A cloud phone system suits most organisations, but it is not magic. These are the honest pros and cons:
| Advantages | Limits to plan for |
|---|---|
| No phone system hardware to buy, house or maintain | Call quality depends on your internet connection and network |
| Users can work from any site, from home or on a mobile app | In a power cut, routers and desk phones stop unless you have backup power; mobile apps can carry on over mobile data |
| Add or remove users and change call flows quickly | Ongoing licence costs replace a one-off hardware purchase |
| Calls can divert automatically if a site goes offline | Analogue devices such as alarms and door entry may need adapters or another solution |
| Updates and security patching handled by the provider | You depend on the provider's platform and support |
| Not affected by the PSTN and ISDN switch-off | Emergency call locations must be kept up to date as people move |
For the full comparison with an on-site system, read hosted vs on-premise phone systems.
Types of cloud phone system
Cloud phone systems come in a few flavours, and we supply all of them:
- Hosted PBX platforms run by a provider, such as Forever UC, hosted 3CX and BT Cloud Voice (cloudvoice.cloud)
- Calling inside collaboration apps: Microsoft Teams Phone, including Forever Teams, and Webex Calling in the Webex App
- Self-hosted cloud systems: 3CX can also run in your own Amazon, Azure, Google or DigitalOcean account
- SIP trunks are not a phone system in themselves; they connect a PBX you own to the phone network
To find out what a system would cost, see cloud phone system cost, or contact us for a recommendation.
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
Is a cloud phone system the same as VoIP?
Not quite. VoIP (voice over IP) is the technology that carries calls over a data network. A cloud phone system is a complete business phone system, with extensions, menus, groups and voicemail, that runs in a data centre and uses VoIP to reach your devices.
Do I need a landline for a cloud phone system?
No. A cloud phone system needs an internet connection, not an analogue or ISDN line. Your existing landline numbers can usually be ported across, so callers still reach you on the same numbers.
What happens to a cloud phone system if the internet goes down?
The phone system itself keeps running in the data centre, so calls can be diverted automatically to mobiles, another site or voicemail. Users with mobile apps can carry on over mobile data. A backup connection at your site reduces the risk further.
Can I use a cloud phone system on my mobile?
Yes. Most platforms, including Forever UC, 3CX, Teams Phone and Webex Calling, have iOS and Android apps, so staff can make and take calls on their business number from a mobile and keep it separate from their personal number.
Does a cloud phone system work in a power cut?
Desk phones and routers need power, so they stop in a power cut unless you have backup power such as a UPS. Mobile apps on charged phones can still make and receive calls over mobile data, and calls can divert to mobiles.