ADSL Technology today

Asymmetric Digital Subscriber Line, ADSL, is a modem technology that transforms ordinary phone lines into high speed digital lines for ultra-fast Internet access. ADSL 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.

What is ADSL and how fast is it?

ADSL modems use digital coding techniques to divide the frequencies used on a phone line to split the data and voice functions. That means you could be simultaneously talking on the phone or sending a fax and surfing the World Wide Web on the same line at the same time. ADSL provides speeds up to 8 Mbps downstream (to the user) and up to 1 Mbps upstream, depending upon the length and loop and line conditions.

What is ADSL used for?

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.

ADSL versus 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. The big difference between ADSL and cable modems, however, is the number of lines available to each. There are no more than 12 million homes passed today that can support two-way cable modem transmissions, and while the figure also grows steadily, it will not catch up with telephone lines for many years. Additionally, many of the older cable networks are not capable of offering a return channel; consequently, such networks will need significant upgrading before they can offer high bandwidth services.

ADSL versus ISDN

The two services are not the same - ISDN provides two voice channels or a 128 kbps data channel while ADSL is predominantly a data pipe providing an asymmetrical bandwidth of up to 8 Mbps downstream and 1 Mbps upstream under good conditions. However, an ADSL access network will run on the existing phone network and therefore will not require the expensive and time-consuming switch upgrades that held ISDN back for so long. If ADSL service prices resemble ISDN service prices, then one would expect ADSL to be favored for Internet and video applications. ISDN is a dialup connection that is metered for usage.

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. 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. 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. 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.
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Infinite Internet Systems, Inc.
134 S 13th St. Ste. 302 Lincoln, NE 68508
Phone: (402) 477-2474
Toll Free: (877) NFI-NITE
Fax: (402) 477-3407