IP PBX stands for Internet Protocol Packet Exchange. An IP PBX is simply a telecommunication unit which provides seamless voice connectivity for personal desk to room phone connections within a commercial building. It supervises the incoming and outgoing calls on its phone network via an internet connection. This facility makes it a boon for all those organizations which have limited number of phone employees.
IP PBX systems are equipped with inbuilt extensions or virtual LANs (VLAN) that can be connected to different networks. By using these extensions, you can gain better voice and data transmission across multiple network interfaces. These virtual connections are created by means of a routing table. A single IP address can be used for various purposes, like connecting virtual branch offices or departments, or connecting a single IP phone to several IP phones. This facility also makes the IP pbx system flexible and enables it to accommodate new business requirements, which require additional phone extensions.
The voice features offered by IP PBXs are amazing. IP telephony provides excellent and crystal clear voice communication. It is capable of making international calls, long distance calls, STD-based calls, voice mail, web conferences, voice mail to email, fax to email, and video teleconferencing. IP phones can be used to manage voice mail, receptionist services, answering services, call forwarding, and VoIP telephony. Some IP telephony providers provide additional features like voice mail delivery, unified messaging, and file sharing applications.
The ip pbx system provides significant advantages over conventional on-premises telephone systems. First of all, IP telephony does not place any long-distance limitations on the user. Calls can be placed anywhere in the world, even if the user is living in a different part of the country. Secondly, IP networks are scalable and can accommodate large call volumes. And the users do not have to be bothered about maintaining a separate telephone network for making local, STD, or ISD calls.
An IP pbx system is very easy to install. A local area network (LAN) with a gateway has to be established between the IP box and the various servers. The IP pbx system can use either dedicated or shared resources for making phone calls. The IP service provider can control and limit the usage of the allocated resources. This helps to ensure that no one else can use the same amount of bandwidth as the calls are being made.
Most IP pbx systems work on the principle of circuits with digital circuits instead of analog ones. Analog signals cannot be transmitted over IP networks because they have high attenuation levels. Digital voice signals have much higher bandwidth and hence they can be transmitted easily over IP networks. Voice over IP (VoIP) solutions based on IP telephony also provide great sound clarity. So business phone systems are very useful not only for large organizations but also small offices.
To understand more about this subject, see this related post: https://en.wikipedia.org/wiki/VoIP_phone.