Copyright 2006 Peter Nisbet

In spite of the growing popularity of IP telephony, there are still many people who do not know what a VoIP phone is. What is the difference between a VoIP phone and an ordinary phone?

As far as you are concerned, probably not a lot. You can still use your own landline phone if need be, though in its simplest form there is no VoIP phone handset as such. Just a microphone and speakers will do. All you need is some software which is supplied by the provider.

You can use your normal land-line phone. Just like digital TV requires a box, either set-top or included in the set, VoIP needs a box which you can either buy yourself, or get from your VoIP provider. Once you connect your phone to the box and the box to your internet connection, you have your VoIP phone system using your own phone. Due to the connection speeds involved you have to have broadband or another high-speed internet connection.

Your telephone conversation passes through the internet in packets in the same way as any other file does. As you speak, your analogue voice signal is digitized by the VoIP software into binary form, and the digital stream broken up into small 'packets' which are sent through the internet. These packets each take their own fastest route through the internet, from computer to computer, till they reach their destination. This is the way that all files are sent through IP.

The problem with a streamed signal, such as a VoIP phone conversation, and a packet system, is that the packets do not always arrive in the correct order. This is due to the releative amount of internet traffic each packet comes up against, and the fact that they can each take different routes. Also, some packets are lost, or 'dropped'.

Modern software is becoming increasingly better at arranging packets in the correct order (often through slight time delays which allow them to be rearranged) and covering up 'dropped' packets. VoIP phone conversations are therefore more audible now than they were in the early days of VoIP phone systems.

As I said, you can use your computer microphone and speakers to make and receive conversations, but you can also get a dedicated VoIP phone if you prefer. It's all a matter of choice and does not significantly affect the services you can have.

Some of the services supplied free with VoIP phone systems are:

* Caller ID
* Call waiting
* Call forwarding
* Voicemail
* Conference calls
* Call transfer
* Group pick-up

Once you have your box, any calls you make to another VoIP are freeanywhere. For calls to non-VoIP phones there is a charge, but this is generally lower than normal land-line charges.

Your phone number relates to the adaptor, so you can take this with you and use it on any computer with fast internet connection. You can also buy a VoIP phone to go with your laptop and make telephone calls anywhere at any time; just as you can with a mobile, but at a fraction of the cost, and usually free to any other IP phone. This is an excellent inexpensive solution for businesses with a network of officesall calls between them will be free throughout the world.

Another cool feature is virtual phone numbers. You can get local area numbers allocated to your regular phone number, so that if your family live in LA and you are in New York they can ring your LA local number with their landline and speak to you in New York at local rates. How cool is that!

A VoIP phone is now an attractive option for anyone, both as a cheap alternative to a mobile phone and as a complete replacement for a landline.