The main principle of VOIP technology is to transform the voice into digital signals which will be forwarded to the broadband internet. This net connection will then help in the conversion of the digital signals into voice before reaching to the listener. The functioning of VOIP phones depend upon broadband internet connection and the quantity of data transfer by broadband internet connection is directly proportional to the bandwidth speed. In other words, bandwidth is the capability to transfer data in a given span of time.
There are two different types of bandwidth. One is the upload bandwidth, which is the quantity of data sent to the internet, and the other is download bandwidth, which is the quantity of data received from the internet. It is always recommended to use the broadband bandwidth of 90 Kbps as VOIP telephone calls utilize 90 Kbps of bandwidth for high sound quality. But if broadband net service provider is unable to provide this much of bandwidth then most of the VOIP service providers provide an option of lowering down the voice quality by lowering down the bandwidth to approximately 60 Kbps or 30 Kbps.