A VoIP PBX is a modern telephony system for the small business or the enterprise. It has been around for many years, however sometimes people take it for granted and do not realize the benefits it provides.

The main concept of an VoIP PBX is that the technology used is Voice Over IP meaning speech is transmitted over computer networks instead of dedicated telephony wires as with the previous technologies. In the past, we used to create a whole different cable network inside a business with wires starting from the data rooms and arriving to the end user desks. These wires would only be used for the telephony system while the computer network would require extra wires, totally isolated.

This isolation in wirings was also reflected in the technical departments of a business. There used to be a separation between IT and Telecomms departments, as the technologies had almost nothing in common and would function completely independent of one another.

At some point in time, Telecomms started merging with IT. This trend continued to the point where now everything is almost totally integrated. I believe that there is a clear winner here, and that is IT and networks, not Telecomms. All voice and video traffic is transmitted over IP networks nowadays. Maybe you can find a small exception somewhere but this is negligible.

The advantages are many. IP PBX systems use the same network as the computers, so there is no need for two separate networks with obvious management need, cost and staff implications. The use of IP networks
is also enabling many enhancements and additional services that would not be possible otherwise. For example, accessing the web page of a desk phone would not be possible when using traditional telephony technologies. Today we can remotely check, troubleshoot and change the setup of a desk phone via it’s web interface which is a small web site with the phone settings.

VoIP PBX systems enable lower costs because a lot of the previously hardware-implemented systems are now software-based. Some years ago you would have to buy heavy hardware and stack it in multiple racks to implement voicemail, add extensions for your new floor in the building and other such. The reason is that each extension in the traditional telephony systems requires a wire from the phone to the PBX and there you have to have a PBX card with a telephony port (called FXS) to accept the phone. Today, you plug the phone on the network and it communicates with the PBX through the network. The PBX does not need any cards, it just needs to have enough processing power.

Apart from the internal extensions, VoIP PBX systems provide benefits with the trunk lines. A trunk line is the connection between the PBX and the Telco – the telephony provider. This used to be an actual wire or wires that ran from your premises to the Telco premises. Examples of trunk lines are PSTN lines, lines based on PCM that carry multiple channels, ISDN PRI lines (E1 size for Europe and T1 for the US), and other similar. The benefit that a VoIP PBX provides is that it can accept SIP trunks, eliminating the need for traditional trunk lines.

A SIP trunk is a multimedia connection between two systems via a network for the purpose of transporting voice or video. SIP Trunks can be formed between a PBX and a provider. The provider will provide access to the public networks (PSTN/ISDN) and convert that traffic to SIP (Session Initiation Protocol) which is based on the IP network protocol. In other words, your telephone lines in your business come from a network connection with the provider or from the Internet. In this way, you can easily upgrade or downgrade your lines, it is only a setting at the provider side. There is no need for digging outside in the road or making connections with wires outside your premises. You can also have many different lines from other areas or countries arriving at your PBX and many other such advantages.

Remote working is another advantage of IP PBXs. You can easily have a remote extension and answer your business phone from home. No one will know …! You just need to login to your VPN or use an intelligent VoIP PBX way of logging in with your extension via TLS or other such technology and you are up and running, part of the internal extensions domain.

Much more can be said about IP PBXs, however these are the basic advantages. Businesses who have chosen to fully embrace IP telephony are having multiple benefits and enjoy high-tech features at much lower costs.

Dionissis Zervas

UC Engineer