Welcome to Linux Knowledge Base and Tutorial
"The place where you learn linux"

 Create an AccountHome | Submit News | Your Account  

Tutorial Menu
Linux Tutorial Home
Table of Contents

· Introduction to Operating Systems
· Linux Basics
· Working with the System
· Shells and Utilities
· Editing Files
· Basic Administration
· The Operating System
· The X Windowing System
· The Computer Itself
· Networking
· System Monitoring
· Solving Problems
· Security
· Installing and Upgrading
· Linux and Windows

Man Pages
Linux Topics
Test Your Knowledge

Site Menu
Site Map
Copyright Info
Terms of Use
Privacy Info
Masthead / Impressum
Your Account

Private Messages

News Archive
Submit News
User Articles
Web Links


The Web

Who's Online
There are currently, 80 guest(s) and 0 member(s) that are online.

You are an Anonymous user. You can register for free by clicking here



Current HOWTO: Modem-HOWTO

Modem-HOWTO: Appendix E: Cable and DSL modems Next Previous Contents

25. Appendix E: Cable and DSL modems

25.1 Introduction

This HOWTO only deals with the common type of analog modem used to connect PC's to ordinary analog telephone lines. There are also higher speed analog modems that use special types of lines: cable and DSL modems. There is also the ISDN "modem" which uses digital signals. While this HOWTO doesn't cover such modems, some links to documents that do may be found at the start of this HOWTO. The next 3 sub-sections: DSL, Cable, and ISDN, briefly discuss such modems. For both DSL and Cable modems, the basic QAM modulation method is similar to ordinary analog analog modems. See Combination Modulation

25.2 Digital Subscriber Line (DSL)

DSL (often ADSL) uses the existing twisted pair line from your home (etc.) to the local telephone office. This can be used if your telephone line can accept significantly higher speeds than an ordinary modem would use. It replaces the analog-to-digital converter at the local telephone office with one which can accept a much faster flow of data (in a different format of course). The spectrum of the twisted pair line is divided up into various channels. Each channel uses QAM modulation like ordinary modems do. Data is sent over multiple channels. The device which converts the digital signals from your computer to the analog signal used to represent digital data on what was once an ordinary telephone line, is a DSL modem.

25.3 Cable Modems

The coaxial cables that provide for cable television in homes have additional bandwidth not used for television, mostly at frequencies higher than used for cable TV. This extra bandwidth may be used for connecting computers to ISP's. However, many computers need to share the same cable. The spectrum of the free bandwidth is split up into channels (frequency division multiplexing) and each channel is given time slots to which individual computers are assigned (time division multiplexing). The cable modem converts the digital date from your computer (from a network card: NIC) to the required analog signal, and only broadcasts within it's assigned time slots on it's assigned channel.

Next Previous Contents

The Linux Tutorial completely respects the rights of authors and artists to decide for themselves if and how their works can be used, independent of any existing licenses. This means if you are the author of any document presented on this site and do no wish it to be displayed as it is on this site or do not wish it to be displayed at all, please contact us and we will do our very best to accommodate you. If we are unable to accommodate you, we will, at your request, remove your document as quickly as possible.

If you are the author of any document presented on this site and would like a share of the advertising revenue, please contact us using the standard Feedback Form.


More information about the site can be found in the FAQ



Security Code
Security Code
Type Security Code

Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.

Help if you can!

Amazon Wish List

Did You Know?
You can help in many different ways.


Tell a Friend About Us

Bookmark and Share

Web site powered by PHP-Nuke

Is this information useful? At the very least you can help by spreading the word to your favorite newsgroups, mailing lists and forums.
All logos and trademarks in this site are property of their respective owner. The comments are property of their posters. Articles are the property of their respective owners. Unless otherwise stated in the body of the article, article content (C) 1994-2013 by James Mohr. All rights reserved. The stylized page/paper, as well as the terms "The Linux Tutorial", "The Linux Server Tutorial", "The Linux Knowledge Base and Tutorial" and "The place where you learn Linux" are service marks of James Mohr. All rights reserved.
The Linux Knowledge Base and Tutorial may contain links to sites on the Internet, which are owned and operated by third parties. The Linux Tutorial is not responsible for the content of any such third-party site. By viewing/utilizing this web site, you have agreed to our disclaimer, terms of use and privacy policy. Use of automated download software ("harvesters") such as wget, httrack, etc. causes the site to quickly exceed its bandwidth limitation and are therefore expressly prohibited. For more details on this, take a look here

PHP-Nuke Copyright © 2004 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Page Generation: 10.8 Seconds