October 10, 2009
This article aims to answer the common question of “What is VoIP?” Many people are asking it nowdays as it seems to have come out of nowhere. Read on for this brief VoIP Intro….. Voice over Internet Protocol (VoIP) is a technology and an emerging set of applications which allows you to make phone calls over a Broadband Internet connection. VoIP can be used to call any telephone anywhere in the world. It doesn’t matter if the person you are calling has VoIP or not, as this is all taken care of by your VoIP Service Provider.
VoIP telephone calls can be made either by using a Personal Computer (PC) connected to the internet, or by a standard telephone which will need to be connected to the internet using a special adapter. Also, newer IP/Broadband Telephones are available, which can connect directly to a cable modem or internet router. Over the last few years, VoIP has become increasingly popular and is already starting to replace existing telephone networks, with some people and businesses choosing to cancel their traditional phone line and use VoIP instead. The main reason people and businesses are switching over to VoIP is because of the significant cost savings that can be made over a traditional service provider. Long distance and International calls are much cheaper, and VoIP Service providers do not have the extra burden and costs to maintain the exiting telephone networks, allowing them to provide their services at greatly reduced costs.
VoIP provides similar features to traditional phone systems, such as voicemail, call forwarding, call waiting, caller ID, call blocking etc. VoIP also offers new features which do not currently exist on traditional phone systems, for example, the ability to have a virtual number – a telephone number from any available area code. This allows you to receive calls from people outside your local calling area with the caller paying only for a local call.
So there you have it, a brief VoIP Intro that answers the “What is VoIP?” question. If you would like to find out more about VoIP, visit the VoIP Articles page where you can find further information on all aspects of the VoIP technology.
October 10, 2009
VoIP is based on the transmission of digital data. It is a process whereby your voice data is split into chunks and sent from a starting point to a destination.
When you make a VoIP telephone call and begin to speak, the first step in any VoIP call is to convert the analogue signal of your voice into digital data. This is done with an Analogue-to-Digital Converter (ADC). As its name suggests, an ADC converts continuous analogue data (e.g. your voice) into smaller pieces which are assigned a numerical value.
Once your voice is digitized, the next step is to compress the audio data using a codec (enCOder/DECoder) which significantly reduces the amount of digital data while maintaining audio quality. The compressed digital data can now be sent over the Internet.
The data stream must be divided into smaller chunks, known as ‘packets’ which, besides containing the audio data, contains information about the origin, the destination, and a timestamp that allows it to be reconstructed in the correct sequence.
All data that is sent over the Internet is encapsulated in ‘layers’ which aid in its proper delivery. For example, web pages use the Internet Protocol (IP) network layer to specify destination and origin addresses, the Transmission Control Protocol (TCP) transport layer to create a connection between two computers and the Hyper Text Transfer Protocol (HTTP) as an application layer to allow the Web browser to display the web page correctly.
Most VoIP uses a transport layer called User Datagram Protocol (UDP) which is faster than TCP. A commonly used application layer is called Real-time Transmission Protocol (RTP) – originally developed for delivering audio and video over the Internet. RTP provides information about the sequence of the data packets so they can be reconstructed in the correct order at their destination.
RTP also has the ability to drop packets if they do not arrive within a certain amount of time. This is necessary for telephone conversations because if the telephone software waited for every packet of information to arrive before reassembling it there would be unacceptable delays in the audio stream.
Even though some of the packets are dropped, there is usually still enough information to make the conversation legible. The number of packets that will be dropped depends on the speed of your Internet connection in the distance between the two parties.
In order for voice data to be transmitted without any noticeable delays, a broadband Internet connection is necessary. Many households and businesses are already using broadband (either DSL or cable) so adding VoIP is fairly simple. Once the voice data has arrived at its destination, it is reassembled in the correct order and converted back from digital to analogue, allowing the person at the receiving end of the call to hear it