What is IP PBX? (Internet Protocol Private Branch Exchange)?

The following document is about IP PBX, it is a kind of PBX that works and makes connections through the Internet. It can be a hardware (physical object) or a software system (installed on a computer). Its task is to carry both video and audio data over a data network (e.g. the Internet). Read about the definition of IP PBX, learn how many types of PBX exist and how they really work in practice.

The IP PBX is a business telephone system. This system switches calls among VoIP users on local lines. The users may use an external phone line.

The IP PBX system can work with PSTN (Public Switched Telephone Network). It switches calls between a user who uses VoIP and one who uses an ordinary phone or it can switch calls between users using ordinary phones (Figure 1). In Figure 1 you can see that a VoIP phone initiates a call through the Ozeki Phone System to different kinds of phones: analog and VoIP phones. The VoIP phone can call the analog phone through a gateway, and it can call another VoIP phone with the help of the SIP (Session Initiation Protocol) protocol. Extra functions can be added to the system like video conferencing, live calls, IVR (Interactive Voice Response) etc.

what is ip pbx
Figure 1 - What is IP PBX?

The Four Types of PBX:

  1. Analog PBX (Signals are not converted into digital codes.)
  2. Digital (Signals are converted into digital codes.)
  3. IP PBX/VoIP PBX (Signals are transmitted through IP network.)
  4. Hybrid (Mixture of Digital and IP PBX.)

The latest type of this kind of system is the VoIP PBX/ IP PBX that uses Internet to make calls.

The IP PBX system is a software based PBX system that carries out tasks and services that a PABX server cannot provide like packet-switching.

How It Works

The IP PBX is like a proxy server. If you want to make a call from a VoIP phone or a Softphone to another VoIP phone you can do it through the Internet but if you want to call a traditional or mobile phone you can call it through PSTN.

What You Need

  • Strong Server Configuration

    • To be more efficient you can create rules for the order and number of the phones.

  • PSTN Connection

    • If you want to make a call from a conventional or mobile phone, you only need to have an adapter attached to the PBX system.

  • Local Area Network (LAN)

    • The communication will be easy if you install a PBX system on your Local Area Network.

The Roles of PBX

  • connection establishment among users
  • maintenance of connection
  • ends connection between participants
  • contains data

Features of IP PBX

  • Voicemail bypass
  • Call-out
  • Call-pick up
  • Softphone
  • Fax to e-mail etc.

Ozeki Phone System is an outstanding IP PBX. It provides all the functionalities and more than most IP PBX systems. It can switch calls between VoIP phones, traditional analog and digital ISDN phone lines and it handles mobile extensions and can even connect calls and live chat sessions coming from a website.

For further information on IP PBX related topics, read our pages:

More information