VoIP And Bandwidth
VoIP has only become possible through the growth of broadband Internet, as this provides the necessary bandwidth for reliable phone calls.
Bandwidth refers to the amount of data transmitted between computers in a given time period, with Internet connections usually measured in Kilobits Per Second (kbps) or Megabits per second (mbps).
An introductory broadband package is usually rated at 512/128 kbps - that is, 512kbps downstream - to your computer - and 128kbps upstream, to the Internet.
A good-quality voice call needs 64kbps of bandwidth, but most VoIP services recommend a minimum bandwidth of 90kbps - in both directions - for reliable voice calls. A standard ADSL or cable modem service should achieve this easily, but there are number of other factors to take into account.
If you have other users on your network, want to run more than one VoIP line or have other applications that send or receive a lot of data, an entry-level Internet connection might not be enough.
Most Internet connections are also "contended", meaning the bandwidth can be shared by other users. Residential services often have a 50:1 contention ratio; 20:1 is more common for business.
Although most services rarely reach their full contention ratio, the higher speed your Internet connection, the better the chance of making a high-quality phone call.
