PBX stands for private branch exchange, a localized switching system that routes calls between internal users and connects them to the external public telephone network. It allows an entire office to share a limited number of outside lines while providing features like internal extensions, call routing, and voicemail. Older systems relied on physical hardware cabinets, while many setups rely on software-based or cloud-hosted routing.
I need you to punch down the new extensions in the server room and configure them in the PBX.
A cloud-hosted PBX is often called a virtual PBX or IPBX, shifting the switching logic from a closet rack to a data center.
Related terms
Private branch exchange
A private telephone switching system installed on a customer premises.
PSTN
The global infrastructure of circuit-switched telephone networks operated by national and regional carriers.
Extension
A short internal telephone number assigned to a specific endpoint within a private branch exchange.
POTS
Plain old telephone service is the traditional analog voice transmission network using copper wires.