If you have an ear open to new computer technologies, you are
sure to have heard about VoIP. Voice over Internet Protocol
(VoIP) is an emerging set of applications which allows you to
make telephone calls over the Internet. It is already starting
to replace existing telephone networks, with some people and
businesses opting to cancel their traditional phone line and use
VoIP instead.
VoIP was originally developed to provide voice communication
between computer users in different locations. Although it still
has this application, it has been further developed into a
telephone network in its own right. People using VoIP can call
any telephone anywhere in the world and can receive calls on
telephone sets connected to the Internet or Local Area Network
(LAN).
Background
It all started back in 1995 when Israeli computer enthusiasts
made the first computer to computer voice connection. In the
same year this technology was developed into a software package
called Internet Phone Software. All that was needed to talk to
another computer user was a modem, sound card, speakers, and a
microphone.
The software digitized and compressed the audio signal before
sending it over the Internet in data packets. These voice
connections could only occur between computers which had the
software installed. The sound quality was very poor — nowhere
near the quality of standard telephone connections.
The technology continued to be developed and by 1998 gateways
had been established to allow PC-to-phone connections. Later
that same year phone-to-phone connections that used the Internet
for voice transmission were set in place. These phone-to-phone
connections still required a computer to initiate the call, but
once the connection was established, the callers could use a
regular phone set.
VoIP Today
There are currently many VoIP services available for residential
and commercial use. Some of these still rely on PC-to-PC
connections but may offer other services such as PC-to-phone and
phone-to-phone.
Internet phones are available that plug into the sound card or
USB port of a computer. These phones may have number pads and
ringers that allow you to use them the same as traditional
telephones. The computer can be bypassed completely by
connecting a phone directly to a broadband modem (either DSL or
cable).
How Does It Work?
The first step in using VoIP is converting your voice into
digital data. This is done by \’sampling\’ your voice — dividing
the analog sound signal into discrete steps that can be assigned
a number value. Once your voice is digitized, the data can be
compressed.
This compressed digital data is split up into \’packets\’ of about
1500 bytes that can be transferred over the Internet. As well as
the voice data, the packets contain information about their
origin, their destination, and a timestamp that allows them to
be reconstructed in the correct order. Once they arrive at their
destination, they are reassembled and converted from digital
back into analog so that the receiving party can hear your
voice.
In order for voice data to be transmitted without noticeable
delays, a broadband Internet connection is necessary. Many
households and businesses are already using broadband (either
DSL or cable) so adding VoIP is relatively simple.
About the author:
Mark is a technology consultant in the great Orlando area. His
blog can be read online at http://www.voipblogonline.com.