PBX

Effective internal and external communication is facilitated by a connection to a public switchboard, which is made possible by Private Branch Exchange (PBX), a private telephone network that serves as an internal switchboard.
An improved internal communication system is a PBX’s main benefit. Employees can easily communicate with one another without using separate phone lines by using short extensions or internal lines rather than full phone numbers. Additionally, coworkers can share phone lines. Since there is no use of an external switchboard, this is essentially free. However, a conventional PBX system needs pricey switchboard hardware, phone line wiring, and constant maintenance.
An IP PBX is an advanced PBX system that communicates with current broadband infrastructure using the Internet Protocol.