Glossary Core concepts
What is Hosted PBX?
Also called cloud pbx, hosted phone system, cloud phone system, virtual pbx
A hosted PBX is a business phone system where the call-handling equipment lives in the provider's data centre rather than in a cupboard at your office. Your handsets and apps register across the internet to that system, and everything a traditional PBX did, extensions, transfers, hold, voicemail, auto attendants, call queues, is delivered as a service.
What changes compared with on-premises
The functional difference is smaller than the operational one. Users still dial extensions and press transfer. What changes is who owns the risk: upgrades, patching, hardware failure and capacity planning move to the provider, and the cost moves from a capital purchase every seven to ten years to a monthly per-user fee. It also decouples the phone system from the building, which is what makes remote and hybrid working straightforward rather than a project.
Hosted PBX versus SIP trunking
These get compared as if they were alternatives, and for a business with an existing PBX they are. If your phone system works and you only want cheaper, more flexible lines, buy SIP trunks. If your phone system is the problem, or you do not have one, buy a hosted system. The deciding question is whether you have equipment worth keeping, not which technology is better.
What to ask before you migrate
Three questions save most of the pain. Can you keep your existing numbers, and what does porting cost. Will your current handsets work, since many IP phones can be reprovisioned to a new platform and replacing fifty of them is a real expense. And what happens to the phone system if the internet at a site goes down, because a hosted system depends on connectivity in a way an on-premises one does not, and the answer should be a specific failover behaviour such as rerouting to mobiles rather than a shrug.