What Is Hosted PBX? Cloud Phone Systems Explained Simply

If you have been researching business phone systems, you have probably come across the term "hosted PBX" alongside cloud phones, VoIP, and UCaaS. The jargon can be confusing, but the core concept is straightforward: a hosted PBX is a business phone system that lives in the cloud instead of in your office.

This guide explains what hosted PBX actually is, how it works, what it costs, and whether it is the right choice for your business.

What Does PBX Mean?

PBX stands for Private Branch Exchange. It is the system that manages internal and external phone calls for a business. In practical terms, a PBX:

• Connects internal extensions so staff can call each other
• Routes incoming calls to the right person or department
• Connects internal phones to the outside phone network for external calls
• Provides features like voicemail, call transfer, hold music, call queues, and auto attendants

Traditionally, a PBX was a physical box (or rack of equipment) sitting in a server room or comms cupboard in your office. It connected to BT lines on one side and your desk phones on the other.

What Makes It "Hosted"?

With a hosted PBX, that equipment is no longer in your office. Instead, it runs on servers in your provider's data centre (the "cloud"). Your desk phones connect to the hosted PBX over the internet rather than over internal wiring to a local box.

The Key Difference

• Traditional PBX — hardware on your premises, connected to phone lines, maintained by you or your IT team
• Hosted PBX — software running in the provider's cloud, connected via your internet, maintained by the provider

From the user's perspective, the experience is identical. You pick up a phone, dial a number, and make a call. The technology behind it is just in a different place.

How Hosted PBX Works

The technical flow is straightforward:

1. Your VoIP phones connect to the internet — they plug into your network like any other device and connect to the hosted PBX server via your broadband
2. Call signalling goes to the cloud PBX — when you make or receive a call, SIP (Session Initiation Protocol) messages travel between your phone and the hosted platform
3. Audio travels over the internet — the actual voice data (RTP packets) flows between your phone and the provider infrastructure, which connects to the public phone network
4. The hosted PBX handles all the logic — routing, voicemail, call queues, time-based rules, IVR menus, and recording all happen in the cloud

All you need on-site is an internet connection and VoIP phones (or softphones on computers and mobiles).

What Features Do You Get?

A hosted PBX typically includes far more features than a traditional system, because adding features is a software update rather than a hardware purchase:

Standard Features

• Auto attendant / IVR — automated call routing ("Press 1 for Sales")
• Call queues — hold callers in line with music and position announcements
• Voicemail — with email delivery and transcription
• Call recording — automatic or on-demand recording of all calls
• Call transfer — blind and attended transfers between extensions
• Ring groups and hunt groups — ring multiple phones simultaneously or in sequence
• Time-based routing — different call handling for business hours, lunch, weekends, and holidays
• Music on hold — custom audio for callers waiting

Advanced Features

• CRM integration — screen pops showing caller information when the phone rings
• Call analytics — real-time and historical reporting on call volumes, wait times, and agent performance
• Mobile apps — make and receive calls on your business number from your smartphone
• Video conferencing — some hosted PBX platforms include video as standard
• Microsoft Teams integration — use Teams as your phone interface with calls routing through the hosted PBX
• Presence — see which colleagues are available, on a call, or away

Hosted PBX vs Traditional PBX

Cost Comparison

• Traditional PBX — £2,000-£10,000+ upfront for hardware, plus £500-£2,000/year for maintenance, plus BT line rental, plus call charges. Expansion requires purchasing additional hardware.
• Hosted PBX — £0 upfront (phones may be included or rented), £8-£25 per user per month including calls, maintenance, and updates. Scales instantly by adding users.

Maintenance and Updates

• Traditional PBX — you are responsible for maintenance, or you pay for a support contract. Firmware updates require an engineer visit. Hardware eventually reaches end-of-life.
• Hosted PBX — the provider handles all maintenance, updates, and security patches. You never have to worry about hardware failure in your server room.

Reliability

• Traditional PBX — if the hardware fails, calls stop until it is repaired. If your office floods or loses power, the system is offline.
• Hosted PBX — runs in redundant data centres with automatic failover. If one server fails, another takes over. Your phone system is independent of your office infrastructure.

Remote Working

• Traditional PBX — remote workers need VPN connections or separate solutions. Extending the system beyond the office is complex and expensive.
• Hosted PBX — works from anywhere with internet. Staff at home, in a co-working space, or overseas connect as easily as in the office.

Is Hosted PBX Right for Your Business?

Hosted PBX Is Ideal If:

• You have remote or hybrid workers who need full phone system access
• You want predictable monthly costs rather than large upfront investments
• You do not have (or want) in-house IT expertise managing phone hardware
• You need to scale up or down quickly as your business changes
• You have multiple locations that need to operate as one phone system
• Your current phone system is reaching end-of-life

Traditional PBX May Be Better If:

• You have very specific compliance requirements that mandate on-premises data storage
• Your internet connection is unreliable and you cannot upgrade it
• You have already invested heavily in recent on-premises hardware

For the vast majority of UK businesses in 2026, hosted PBX is the better choice. The traditional PBX use case shrinks every year as internet reliability improves and cloud platforms mature.

What About Microsoft Teams?

Many businesses ask whether they should use Microsoft Teams instead of a hosted PBX. The answer depends on your needs:

• Teams with Calling Plans — Microsoft handles everything, but features are limited compared to a full PBX (basic call queues, no advanced routing)
• Teams with Direct Routing — a hosted PBX provider connects your phone system to Teams, giving you the best of both worlds: the Teams interface with full PBX features underneath

If your team already lives in Teams for chat and video, adding voice through a hosted PBX with Teams integration is often the most seamless approach.

For a full comparison of the top hosted VoIP and PBX providers in the UK, see our hosted VoIP solutions guide. And for small businesses comparing providers and pricing, our small business VoIP comparison breaks down the options from £6 per user.