On-site: remote is an add-on
Connecting a home worker to an on-site PBX usually means a VPN, a session border controller or a separate remote-worker licence. It works, but each remote user is an exception to manage.
Educational comparison
Cloud PBX vs on-site PBX: ownership, upkeep and the way across
A PBX is the switch that routes calls inside a business. It can be a box in your server room that you own, or a service you subscribe to. The difference shows up in who fixes it, how remote people connect and how hard it is to grow.
- Ownership and maintenance compared plainly
- Remote users and scaling
- SIP trunking for those who keep their PBX
Example
Incoming call+1 (416) 555-0198
Main menu9–17
11 — Appointments
22 — Renewals
33 — Billing
After hours
Reception queue90 s → Callback offered
AI receptionist
Voicemail to email
A traditional PBX is hardware you own and maintain on site, with calls delivered over lines or trunks and remote users connected through extra configuration. A cloud PBX is the same routing delivered as a service over the internet, with the provider maintaining it and users connecting from any location by app or desk phone. Businesses that want to keep an existing PBX can add SIP trunking instead of replacing it.
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The same job, two places to do it
Both kinds of PBX do the same work: answer the call, play the menu, ring the right extensions, hold and transfer, take voicemail. The difference is where that logic runs and who is responsible for it.
An on-site PBX is a physical system in your building. You bought it, someone installed it, and someone maintains it. A cloud PBX runs on the provider's platform. You configure it through a console or through the provider's specialist, and the provider keeps it patched, backed up and running.
PBX (Private Branch Exchange)
The private switch that connects a company's extensions to each other and to the outside world.
Learn more: PBX (Private Branch Exchange)Cloud PBX (hosted PBX)
A business phone system run by a provider and delivered over the internet, with no switch on site.
Learn more: Cloud PBX (hosted PBX)Hosted PBX
The PBX as a service: endpoints, extensions, dial plans, failover and admin.
Learn more: Hosted PBXOwnership and maintenance
| Question | Traditional on-site PBX | Cloud PBX |
|---|---|---|
| Who owns the equipment? | You do, along with the room, power and backup it needs | The provider; you own numbers and configuration |
| Who applies updates and fixes faults? | Your IT team or a maintenance contractor | The provider, as part of the service |
| What happens when a component fails? | Calls stop until a part arrives or a technician visits | The provider's platform is designed for continuity; your side needs internet and devices |
| How are changes made? | Often by a technician or a specialist administrator | Through a console, or by asking the provider's specialist |
| What does growth require? | Licences, cards or a larger chassis | Adding a user |
Remote users and multiple sites
Cloud: every user is already remote
The PBX is not in your building, so the office and the home worker connect the same way. Presence, transfers and voicemail work identically in both places.
Sites on one system
A cloud PBX puts several locations on one directory with site-specific numbers and hours. Doing the same with on-site systems means linking separate PBXs or centralising one and connecting the rest.
Where the risk sits
With an on-site PBX, a building outage takes the phones down. With a cloud PBX, a building outage moves calls to the app or another site if that rule is set.
Remote work
Business calls on personal devices, without handing out anyone's cell number.
Learn more: Remote workMulti-location business
Every branch on one system, with its own number, hours and greeting.
Learn more: Multi-location businessMulti-location phone system
Plan the rollout, keep every site's number, pay one bill.
Learn more: Multi-location phone systemScaling up and scaling down
- Cloud: a new hire is a new user; a departure is a removed user. There is nothing to order.
- On-site: capacity is bought in blocks. Running near the limit means planning an upgrade; running well under it means paid-for capacity sitting idle.
- Seasonal businesses benefit from cloud pricing that follows headcount. A fixed on-site system costs the same in the quiet months.
- Feature growth differs too. Adding a contact centre, an AI receptionist or business SMS to a cloud system is a configuration change; on-site it can be a new module or a separate product.
Contact Centre
Queues, routing and supervision for teams that live on the phone.
Learn more: Contact CentreAI Receptionist
Answers, understands and books — in English and French.
Learn more: AI ReceptionistBusiness SMS
Text from the number customers already call — as a team, not from a personal phone.
Learn more: Business SMSSIP trunking: keep the PBX, change the lines
Not every business is ready to retire a PBX that works. SIP trunking replaces the physical lines feeding an on-site PBX with a connection over the internet. The PBX keeps doing the routing; the trunk carries the calls and the numbers.
This is a middle path. You keep your equipment and your existing configuration, gain flexible call capacity and simpler number management, and can plan a later move to a cloud PBX without a second disruption. 3CTel provides SIP trunking for exactly this case and helps scope the eventual migration when it makes sense.
SIP Trunking
Carrier-grade SIP trunks for the PBX you already run — channels, DIDs and failover sized to your traffic.
Learn more: SIP TrunkingSIP trunking
Canadian numbers and call paths for the PBX you already run.
Learn more: SIP trunkingSIP trunk
An internet connection between your own PBX and the public phone network, replacing physical lines.
Learn more: SIP trunkSIP (Session Initiation Protocol)
The signalling standard that starts, changes and ends VoIP calls.
Learn more: SIP (Session Initiation Protocol)The migration path
Document the current PBX
Extensions, menus, ring groups, hours rules, voicemail boxes and any devices such as door phones or fax lines are listed with a specialist.
Rebuild the flow, not the config
The cloud system is designed from what callers should experience, which is often simpler than what the old PBX accumulated over the years.
Test on a temporary number
The new system is configured and tested while the old PBX keeps working. Staff install apps and try calls before anything changes.
Port and switch
Numbers are ported on a confirmed date, all at once or site by site. The old PBX can stay powered as a fallback until you are satisfied.
Decision table
| Situation | Keep on-site PBX | Add SIP trunking | Move to cloud PBX |
|---|---|---|---|
| Recently bought PBX, in-house IT, one site, no remote staff | Fits | Fits if lines are the pain point | Optional |
| Ageing PBX, maintenance contract ending | Costly to extend | Buys time | Fits |
| Staff at home or across several sites | Awkward | Does not solve it | Fits |
| Headcount changes seasonally | Fixed cost | Trunk capacity can flex | Fits |
| Want AI receptionist, queues, texting and reporting | Depends on the PBX | Depends on the PBX | Fits |
| Poor internet at the main site | Fits for now | Needs a stable connection | Needs a stable connection |
Straight answers on PBX decisions
Is a cloud PBX less secure than an on-site one?
Neither is inherently more secure; the risks differ. An on-site PBX is exposed to whatever your building and network allow, and to unpatched software. A cloud PBX relies on the provider's platform practices and on your account controls. Ask any provider how accounts, devices and recordings are protected, and keep your own passwords and access lists current.
What does SIP trunking change for callers?
Nothing they notice. Calls still arrive at the same numbers and the PBX still answers them. What changes is behind the scenes: the physical lines are replaced by a connection over the internet, call capacity becomes easier to adjust, and adding or moving numbers no longer requires a carrier visit.
Related pages.
Hosted PBX
The PBX as a service: endpoints, extensions, dial plans, failover and admin.
Learn more: Hosted PBXSIP Trunking
Carrier-grade SIP trunks for the PBX you already run — channels, DIDs and failover sized to your traffic.
Learn more: SIP TrunkingCloud phone system
No server in the closet. One portal for every user, site and rule.
Learn more: Cloud phone systemEnterprise
Contact centre and back office on one platform, migrated in stages.
Learn more: EnterpriseVoIP vs landline
What changes when business calls move to the internet, and when they should not.
Learn more: VoIP vs landlineCloud PBX (hosted PBX)
A business phone system run by a provider and delivered over the internet, with no switch on site.
Learn more: Cloud PBX (hosted PBX)Frequently asked questions.
In everyday use the terms mean the same thing: a PBX run by a provider and delivered over the internet. Some people use 'hosted' for a dedicated instance and 'cloud' for a shared platform, but the ownership and maintenance picture is the same.
Not always. Phones that use SIP can often be reprovisioned, subject to a check. Many businesses move most users to the desktop and mobile apps and keep handsets only where someone sits at a counter or reception desk.
It varies by make and support contract, and no general figure is given here. The practical signal is when parts, updates or the maintenance contractor become hard to get; that is when businesses start comparing the cost of extending against the cost of moving.
Yes. A common pattern is to trunk the existing PBX first, then move departments or sites to the cloud PBX one at a time while the trunk keeps the rest running. Numbers are moved as each group switches.
Get a read on your PBX before you commit either way.
A specialist will look at what you have, what it costs to keep, and whether trunking or a full move fits. You get a written recommendation and a quote.