Private Automatic Branch Exchange
(PABX) has been a backbone of inter and intra-organization voice communication for decades. This is a managed private network within an organization that consists of many lines and stations. PABX uses a range of different platforms such as Voice over Internet Protocol (VoIP), Integrated Services Digital Network (ISDN) and more for communication. In a or PABX phone system, Public Switched Telephone Network (PSTN)is used for facilitating connections provided by the service provider.