A PBX is a local phone system created specifically for a company or group. Only a small number of exterior phone numbers can be shared by a sizable number of people.

A private branch exchange is an interior telecommunications system that also allows customers to connect to public switched telephone network (POTS) lines for exterior communication. Users are given extensions, which act as special IDs within the PBX, rather than being required to have a phone number. Callers from the outside can input a single phone number to contact multiple individuals by providing their prefix.

Conventional PBX

Individual lines and a local management device make up a conventional PBX phone system. Both internal user contacts and exterior messages are handled by the management unit (also known as the "base server"). It contains a storing system for contact records and voicemails.

Early PBX systems were entirely analog, requiring analog phone connections for all contact. Modern "conventional" PBX systems have digital lines and sometimes use Ethernet connections for interior communication lines instead of telephone cords. When contacting external lines, digital impulses are occasionally converted to analog through a procedure known as SIP trunking.

Hosted PBX

A cloud-based alternative that eliminates the need for a local management system is a shared PBX. Each user, instead, has a VoIP phone that is immediately connected to a gateway or switch. Through a software interface, usually accessed through a web computer, the PBX supervisor can add, delete, and control users.

Users do not have to live in the same geographic place because a shared PBX is cloud-based. A online Phone is therefore perfect for companies with distant employees.