Representative scene contrasting hosted work with a premises closet.
Cost
On-premise systems need upfront hardware, licenses, and maintenance contracts. Cloud PBX is a per-seat subscription with no server to buy or replace.
Maintenance and updates
With on-premise, you or a vendor patch and upgrade the system. With cloud PBX, the provider runs updates and capacity.
Remote and mobile work
Cloud PBX extensions work from a desktop or mobile app anywhere with internet. On-premise systems often need VPNs or extra licensing for remote users.
Reliability and control
On-premise keeps working on the local network during an internet outage, but a power or hardware failure takes it down. Cloud PBX depends on your internet connection; plan for a backup connection and mobile fallback. On-premise gives you full control of the hardware; cloud gives you less to manage.