Upgrading and Repairing Networks

How Cable Modems Differ from xDSL Broadband Access

DSL is a dedicated connection from your location to the telco's central office using your existing phone line. A cable modem gives you access to a shared network media, similar to the older Ethernet technology. This shared network media is nothing more than a part of the signal that travels through the coaxial cables used by cable companies to deliver service to your home or business. Just as the bandwidth of ordinary twisted-pair copper cables is actually used for voice transmissions, an almost-similar situation exists for coaxial cabling from your cable company. Digital cable signals use channels, which are basically time slots in which each channel is sent in a channel of usually 6MHz. Cable companies need only set aside some of these slots for cable service instead of for channels that no one ever watches anyway.

Cable modems also give you a higher bandwidth for downloading from the Internet, when compared to DSL solutions. As cable segments become overpopulated, your performance may vary, depending on other users' habits and the capacity provided to your local neighborhood. Performance may vary from hour to hour, depending on when the service is being used by your neighbors. This is becauseand this is important to remembercable segments are shared media. If you are the only person in your neighborhood using a coaxial cable that terminates at the cable company, you'll have the best cable service possible! If you have several dozen other cable modems on your segment, all must share the available bandwidth on the shared coaxial cable. Don't worry, howeveryour TV channels will still work just as well as ever!

For many users, cable modems are a welcome solution for those who have phone lines that cannot be provisioned for DSL service. Almost everyone within even a small city can obtain cable TV services, whether or not the local telco can provide DSL service. By offering Internet access over existing equipment, a cable company can add a router and connect cable segments to a large Internet pipeline and generate extra revenue from existing customers. Offering cable Internet service also is a good selling point for attracting new customers. Because the cable TV market is now pretty much saturated, cable companies need a new technology to offer in order to keep growing.

For some small-business access, and especially for many home users, cable modem access is a great solution. Whereas DSL requires that the telephone company provision the line (remove bridge taps, voice coils, and so on) and test it to determine the bandwidth that can be supported, cable modems can be purchased in an electronics store and self-installed. Or you can have someone from your cable company install the cable modem. After you have cable TV installed, adding a cable modem is simple.

No matter which technology you want to use, it really comes down to the simple matter of what is available in your location. In some places you may be able to get DSL access, and in others cable modem access. Yet in more competitive environments you might have a choice between the two.