This article is a brief introduction about connecting a PBX to the outside world
in relation with Ozeki VoIP SIP SDK. After reading through this page you will be
fully familiar with all the essential terms concerning PBX connection
and what you will need for creating your own solution using Ozeki VoIP SIP SDK.
Private Branch Exchange (PBX) is a hardware or software solution that establishes the connection between the registered
VoIP clients. The registration process and the connection establishment and disconnection
is made by using SIP (session initiation protocol) messages.
Please be informed that PBX development support is available in Ozeki VoIP SIP SDK from version 10.0
The PBX is connected to the Internet through standard protocols like any other
device or program. The SIP messages are usually send as TCP or UDP packets through
The PBX can also be connected to the PSTN (public switched telephone network). This is an other way to
connect the PBX to the outside world. For this purpose you only need to have a
special adapter that registers to the PBX with a SIP account and from that point the
PSTN network works as a single VoIP end point.