Are DSL & Cable Modems the Same?

By Gissimee Doe

Cable and DSL broadband Internet services use different modems and different technologies.
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Digital subscriber line (DSL) and cable are two delivery methods for broadband Internet services, especially to home users. Both methods allow users to access the Internet at much faster speeds than a dial-up Internet connection. There are some differences in the way in which the methods work, and different modems are needed to convert the signal from DSL and cable to a format a computer can use. Cable is transmitted through cable lines, while DSL is transmitted through the telephone wires. The speeds of cable and DSL Internet access also may vary.


Cable broadband is Internet access delivered over cable lines. Cable is usually provided by a cable television provider. It makes use of a portion of the cable line for providing data, while the rest provides television signals. Cable is shared by members of a community who access the same cable line. The data signal is converted to a signal readable by a computer by a special cable modem. Cable modem speeds can be as fast as 30 megabits per second.

Advantages and Disadvantages of a Cable Modem

Cable broadband Internet access is normally readily available to users with an existing cable television setup. Cable Internet service is always on, with no need to dial up or to log on or log off of the service. The speed of the service does not vary significantly based on the distance from the service provider. However, because the same cable is used to provide service to all members of a community or in a specific region, the speed of access to the Internet will slow down when many people are connected or during peak usage periods.


Digital Subscriber Line (DSL) is Internet access delivered over the telephone lines. A special modem is required to convert the signals into a format the computer can use and back into a format that can be transmitted over the telephone wires. There are different types of DSL, which provide advantages and higher usage speeds than regular DSL. Asymmetric Digital Subscriber Line (ADSL) uses different speeds for upload and download. Very High Bit-Rate Digital Subscriber Line (VDSL) provides speeds that can eclipse cable. Typical DSL speeds go up to 10 megabits per second.

Advantages and Disadvantages of a DSL Modem

Digital Subscriber Line modems need to be connected to a telephone line, which means the subscriber needs to have a landline telephone service. This can add costs for some people. DSL speeds tend to decrease with the distance from the telephone hub. However, unlike cable, there is no decrease in speed when multiple users are connected to the service.