Voice Over IP is jargon for making telephone calls using Internet Protocol. This technology is used by many large and small companies to communicate between sites and from a site to a remote worker.  

Call up a company or friends and relatives from home or the office and the chances are the call will at some stage travel over an IP network, because the technology is now sound enough to form a part of the every day telecommunications backbone for most networks.  

So now you know you are using it, chances are you probably want to know exactly what it is.

Traditional telephony is very simple. On a Public Switch Telephone Network (PSTN) two way conversations travel down a telephone line in a straight line, rather like traffic flowing up and down a motorway in opposite directions.

The advent of the Internet gave rise to a different way of carrying information down the line. Instead of sending everything in a constant stream, IP networks take segments of data, which are sent in ‘packets’ to their destinations. Often these packets will be sent on different routes, aligning themselves in order when they reach the destination. For data this is fine because you are not normally worried over which order the data or the information appears on the screen. With voice, of course, the words you are speaking have to arrive in the right order; hence it has not been until the last few years that the networks have been sophisticated enough to carry voice traffic without any deterioration in quality.

Once businesses and consumers start to make and receive digital calls on the same IP network their data flows in and out on – be that the company LAN or a home broadband connection – a whole new world of opportunities is opened up.

Technical downloads are available under our Useful Reading Section and include:

• Understanding Delay in Packet Voice Networks, written by CISCO
• Installing an IP Telephony Network Using Power over LAN, written by PowerDsine
• The Strategic and Financial Justification for Convergence, written by CISCO
• Integration, Accessibility, Personalisation, written by Mitel
• Extending Enterprise Productivity with Converged IP-Based Solutions, written by CISCO
• 5-Point Guide to Voice over Internet Protocol (VoIP), written by Actimax