How to Integrate IP PBX with the Network

IP PBX system is an IP phone system that supports VoIP services and allows making calls using IP instead of PSTN (public switched telephone network). The advantages of IP PBX phone systems (cheap international calls and long distance calls, easiness and convenience in use and many others) have maid IP PBX one of the most popular types of phone systems.

An IP PBX system is easy to configure and install but you should know the structure of IP PBX phone systems. An IP PBX phone system consists of:

- IP PBX server
- VoIP phones (SIP phones)
- VoIP gateway (optional)

The centre of the IP PBX system is the IP PBX server that performs functions similar to those of a proxy server. All the clients (VoIP phones) are registered with the IP PBX server. When a client needs to make a call the IP PBX server should give the permission to establish the connection.

Clients may be either VoIP phones (SIP phones) or VoIP softphones. In case you want to use ordinary telephones you should fix ATA (VoIP adapters that convert voice into digital data and vice versa).

All VoIP phones (clients) are listed at the IP PBX server along with their SIP addresses. The IP PBX server can establish the connection either through a VoIP gateway or a VoIP service provider. In case you have chosen one of the VoIP service providers there's no need in a VoIP gateway.

A VoIP gateway is used to convert the data used on the telephone lines into the data used over IP. VoIP gateways can be used for two purposes:
- The first one is to convert the telephone lines to VoIP. With VoIP gateway you continue to use traditional PSTN (public switched telephone lines) to receive and place phone calls. This way is preferred by some companies as you can achieve better sound quality by using phone lines.
- The second way is to connect the traditional phone system to the IP network. VoIP gateway then allows making calls through IP using the services of VoIP providers. The cost of internal calls in IP PBX phone system is then reduced to nothing as the calls are transmitted via the Internet.

VoIP gateways are released as external units or as PCI cards. VoIP gateways in the form of external units are more popular. Types of VoIP gateways include analog VoIP gateways (to connect regular phone lines to the VoIP phone system) and digital VoIP gateways (to connect digital lines to the IP PBX phone system). Analog VoIP gateways may connect up to 24 phone lines.