The PABX allows and controls the sharing of different phone lines between different communication devices.
Open this page: http://www.ozekiphone.hu/what-is-pabx-private-automated-branch-exchange-311.html
PABX (Private Automated Branch eXchange) controls the switching of different communication channels among different communication devices. The channel between the devices are built up by Session Initiation Protocol (SIP).
PABX is used by call centers in particular. This system provides single access to multiple lines.
