VoIP, also known as Internet Telephony, is a revolutionary method of transmitting and receiving voice calls across a local or wide area network that has been around in one form or another since the early nineties. Now matured and fully standardised, it is widely deployed in large enterprises and is also popular in the home in some proprietary (i.e. non-interoperable) forms, e.g. Skype, MSN Messenger, Google Talk etc.
Some of the benefits of VoIP above traditional telephony systems are:-
· Reduced calling costs
· Free calls between your sites
· Reduced telephone line charges
· Lower capital costs on new telephone systems
· Integration with legacy telephone systems
· Keep existing telephone numbers even when moving
· Reduced business overheads
· Integration of remote workers
· Handle calls in multiple locations around the World
· Integrate your mobile phones
· Increased business functionality
In VoIP, the audio stream of a telephone call is digitised into 'packets' and transmitted across the data network in the same way as your existing email, web browsing and access to file servers. Calls are made using either a special VoIP phone handset, a software phone on your computer with headphones and a microphone or a regular telephone handset used with a special VoIP adapter (see fig. 1). These devices simply plug into your existing network and using the data switch and cabling are able to establish high quality telephone calls between one another.
Inbound and outbound calls are routed over your broadband Internet connection via a VoIP Service Provider. The service provider allocates you with standard telephone numbers on which inbound calls can be received. The inbound calls are received by the service provider and connected to your VoIP device through the Internet. Likewise, outbound calls are connected via the service provider either between VoIP devices or ‘handed off’ to the PSTN (Public Switched Telephone Network) when calling users on regular wired or mobile telephone systems.
The diagram below provides a visual overview of how a typical VoIP installation works.Click here for an enlarged image
