A PBX, or Private Branch Exchange, is a business oriented phone system that reside at the business location and is used to switch, or connect, calls to business phones or extensions.

A business phone system connects to local phone companies and other business phone systems to provide connections from its extensions to other extensions and the outside world. An IP-PBX uses VoIP (Voice over IP)  technologies for this connectivity.

An IP-PBX  can offer advantages over a traditional or legacy PBX due to its features provided to its users. Automatically connecting you to calls that go to your desk no matter where you are or using a soft phone are just some of the things an IP-PBX can do.

Most older phone systems cannot offer find me/follow me, personalized call screening and presence detection.

Much of the hype about VoIP technologies is that it's free. Those of us with some common sense know that nothing is truly free and VoIP is no exception. Another VoIP feature often claimed is that, unlike older phone systems that need their own wiring, VoIP can use your existing network wiring.

The biggest unknown with VoIP is whether your current network can indeed handle your new VoIP traffic in a reliable manner. This requires some thought and usually an inspection by someone that can monitor and analyze your network traffic. Knowing the maximum number of phone conversations you expect to have at any given instant is an important step in understanding the impact of using VoIP.

One of the problems when using VoIP is that older network equipment doesn't understand what VoIP traffic is. There are certain pieces of information that VoIP sends along with the voice information that informs your network switches and routers that the traffic needs to be a higher priority than plain data.

Since VoIP is just digital data, each piece of network equipment adds a little delay to the voice. If you have a large number of devices in between two VoIP connected phones, a delay of several hundred milliseconds or more is possible.

Most businesses don't have that many devices on their LAN that are in between any two talking extensions. This means that the number of devices is typically not a major concern but should always be checked.

If your business isn't pushing your network to the limits because of large file transfers, heavy printing,  or Internet downloads/uploads, you may be just fine. Using a separate LAN for your VoIP traffic is always an option. If you're installing a new LAN yourself, you probably know that there's usually spare pairs of wires in your network cable that could be used for a second connection just for your phones.

If you already have older phone system wiring and want to use that wiring for your VoIP traffic you may be OK as long as the cabling is Cat 3 or Cat 5. You will have to change the connectors from the typical RJ11 to RJ45s.

Luckily, almost all VoIP phone system resellers understand VoIP issues very well. They can usually take a look at your network wiring and equipment and tell you whether any changes might be required. Don't be afraid to ask them to perform an evaluation of your premises prior to talking about cost.