What is an on-premise IP PBX, and how is it different from cloud PBX?

An on-premise IP PBX is a phone system that runs on a hardware appliance or server physically located at your office, which you own outright. A cloud (hosted) PBX runs on the provider's servers and you pay a monthly per-seat fee. On-prem means a larger one-time spend but full control of your data and configuration; cloud means lower upfront cost and no hardware to maintain. The right choice depends on your priorities around control, connectivity and budget.