Network port(listen mode)–an external application connects to the TCP or UDP port Intercom systems.
feature services available in the public network, such as hunt groups, call forwarding, and extension dialing.
Solid-state digital systems were sometimes referred to as electronic private automatic branch exchanges (EPABX).
The central office lines provide connections to the public switched telephone network and the PBX permits.
An IP-PBX can call-routing activities of the traditional PBX or key system as a software system.
A mobile PBX is a hosted PBX service that extends fixed-line PBX functionality to mobile devices.