Installation guide

12
Chapter 2
ADSL (Asymmetric Digital Subscriber Line)
2.1. What is ADSL?
ADSL is an asymmetrical technology, meaning that the downstream data rate is
much higher than the upstream data rate. It enhances the data capacity of the
existing twisted-pair wire that runs between the local telephone company switching
offices and most homes and offices. ADSL is suitable for Internet users because
more information is usually downloaded than uploaded. For example, a simple
button click in a web browser can start an extended download that includes
graphics and text. ADSL operates in a frequency range that is above the frequency
range of voice services, so the two systems can operate over the same cable.
The advantages of ADSL form the point of view of the Network Service Provider
and the end users:
1. ADSL enables Telcos to use the existing copper wires around the world to
deliver affordable high-speed remote access to the Internet, corporate
networks and on-line services over ordinary phone lines.
2. There is no time wasted for dialing up, ADSL is “always on” and connected,
waiting ready for use.
3. ADSL provides service providers with the capability to use one line to provide
new data services while maintaining the telephone service on the same line,
thus no need to increase any new infrastructures.
4. This new technology empowers the communicating speed nearly 300 times
faster than 24.4 Kbps modems or over 100 times faster than 56Kbps
modems.
5. ADSL enables real-time interactive multimedia applications, such as video