What is ADSL?
Asymmetric Digital Subscriber Line. ADSL is a modem technology that transforms ordinary phone lines (also known as "twisted copper pairs") into high-speed digital lines for ultra-fast Internet access. ADSL also enables access to corporate networks for telecommuters, as well as exciting new interactive multimedia applications such as multiplayer gaming, video on demand and video catalogs.
How does ADSL work?
ADSL modems use digital coding techniques to squeeze up to 99% more capacity out of a phone line without interfering with your regular phone services. That means you could be simultaneously talking on the phone or sending a fax - while surfing the World Wide Web.
How fast is ADSL?
ADSL can provide speeds up to 8 Mbps downstream (to the user) and up to 1 Mbps upstream, depending upon line length and loop and line conditions and also on the service package that you have subscribed with your Internet Service Provider.
What are the benefits of ADSL?
- Simultaneous Internet and voice/fax capabilities over a single telephone line
- Uninterrupted, high-speed Internet access that's always on-line
- Cost-effective solution for residential customers, telecommuters and small businesses
- Data Security that exceeds other technologies
What are the applications you use over ADSL?
ADSL enables two general types of applications -- interactive video and high speed data communications. Interactive video includes movies on demand, other video on demand such as delayed TV segments, video games, video catalogs, and video information retrieval. Data communications covers Internet access, telecommuting (remote LAN access), and specialized network access.
Can the Internet keep up with so much speed?
The Internet infrastructure is constantly being upgraded to handle the rapidly increasing use of the Internet. Many servers operate at 56 Kpbs. In addition, the Internet backbone has grown in an unplanned fashion and a connection may see 20 or more routers, creating significant delay, and for TCP connections, bandwidth throttling. However, a great deal of work is underway to (1) increase server access speeds, (2) improve backbone and NAP bandwidth, (3) increase router speeds, and (4) introduce ATM into the backbone for much lower latency. Futhermore, many Internet service providers will implement proxy or cache servers for frequently visited web pages, creating local access at least for these pages. At the very least, ADSL will make many Internet experiences far much better than voice band modems and the resulting market pressures will inevitably lead to capacity increases.
How does ADSL compare to cable modems?
ADSL provides a dedicated service over a single telephone line; cable modems offer a dedicated service over a shared media. While cable modems have greater downstream bandwidth capabilities (up to 30 Mbps), that bandwidth is shared among all users on a line, and will therefore vary, perhaps dramatically, as more users in a neighborhood get online at the same time. Cable modem upstream traffic will in many cases be slower than ADSL, either because the particular cable modem is inherently slower, or because of rate reductions caused by contention for upstream bandwidth slots.