In short
An IP PBX handles a company’s calls over the data network: extensions, queues, welcome menu, voicemail and forwarding to mobiles. It can be installed on-premise, as a unit in the office rack, or contracted as a cloud service. On-premise gives more control and integration; cloud means less equipment of your own.
Comparison
| Aspect | On-premise PBX | Cloud PBX |
|---|---|---|
| Where it is | A unit in your own office. | The provider’s servers. |
| Control and data | Yours: configuration and recordings in-house. | Held by the provider. |
| Local integration | Direct with door intercoms, paging and analogue lines. | Possible, often with more steps. |
| Costs | Upfront investment and maintenance. | Per-user or per-extension fee. |
| Internet dependency | Internal calls keep working without internet. | No internet, no service. |
Typical features
- Extensions on desk phones, DECT cordless, WiFi phones and mobiles (softphone).
- Welcome menu (IVR), opening hours and out-of-hours forwarding.
- Queues and ring groups for reception, sales or support.
- Voicemail to email and call recording where appropriate.
- Integration with SIP door intercoms and paging.
- Linking several sites as if they were one office.
What to check before migrating
- Current lines and numbers, and whether they can be ported to a SIP carrier.
- Network quality: cabling, PoE switches and voice prioritisation.
- Analogue equipment that must keep working: fax, alarms, lifts.
- How mobile and remote working will be handled.