Introduction To VOIP

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.

Advertisements

Energy and Transport

October 10, 2009

Meanwhile, humans were learning to harness other forms of energy. The earliest known use of wind power is the sailboat.[citation needed] The earliest record of a ship under sail is shown on an Egyptian pot dating back to 3200 BC.[citation needed] From prehistoric times, Egyptians probably used “the power of the Nile” annual floods to irrigate their lands, gradually learning to regulate much of it through purposely-built irrigation channels and ‘catch’ basins. Similarly, the early peoples of Mesopotamia, the Sumerians, learned to use the Tigris and Euphrates rivers for much the same purposes. But more extensive use of wind and water (and even human) power required another invention.

The wheel was invented in circa 4000 BC.

According to archaeologists, the wheel was invented around 4000 B.C. The wheel was probably independently invented in Mesopotamia (in present-day Iraq) as well. Estimates on when this may have occurred range from 5500 to 3000 B.C., with most experts putting it closer to 4000 B.C. The oldest artifacts with drawings that depict wheeled carts date from about 3000 B.C.; however, the wheel may have been in use for millennia before these drawings were made. There is also evidence from the same period of time that wheels were used for the production of pottery. (Note that the original potter’s wheel was probably not a wheel, but rather an irregularly shaped slab of flat wood with a small hollowed or pierced area near the center and mounted on a peg driven into the earth. It would have been rotated by repeated tugs by the potter or his assistant.) More recently, the oldest-known wooden wheel in the world was found in the Ljubljana marshes of Slovenia.[35]

The invention of the wheel revolutionized activities as disparate as transportation, war, and the production of pottery (for which it may have been first used). It didn’t take long to discover that wheeled wagons could be used to carry heavy loads and fast (rotary) potters’ wheels enabled early mass production of pottery. But it was the use of the wheel as a transformer of energy (through water wheels, windmills, and even treadmills) that revolutionized the application of nonhuman power sources.


How VOIP Works

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