I can just hear people asking this question. Unfortunately, I think the answer is “No.” Typically, a digital subscriber line (DSL) modem connects with either an ADSL modem or a cable modem that connects to your ISP through a coaxial cable. Since DOCSIS and ADSL do not work well together, it is not possible to use one modem to connect to both cable and DSL.
Why can not use a cable modem for ADSL connection
The phone system is completely different and was not designed to handle high speed data. DSL (Digital Subscriber Line) uses a standard copper phone wire, but at frequencies above the voice band.
The higher frequencies are modulated with digital data and are used for both upstream and downstream traffic. An ADSL modem takes standard telephone signals, filters out the voice band, and demodulates (recovers) the digital signals.
A standard telephone can be plugged into an ADSL modem so that in addition to Internet access you can make and receive phone calls.
The most obvious issue is that the inputs on a DOCSIS cable modem and an ADSL modem are different: a cable modem connects to the utility by means of a screw-on “F” connector attached to a coaxial cable.
This cable carries a broad spectrum of RF signals with connectors at frequencies originally intended for TV broadcast signals. The modem contains tuning circuits which lock onto as many as 48 of these channels at a time and then use industry-standard bonding techniques to generate an error-corrected bi-directional bitstream that is translated to the standard network protocol available on the modem’s Ethernet port.
As the name implies, DSL (Digital Subscriber Line) is a digital service that runs over your phone line. However, DSL doesn’t tie up your phone line, so you can use your computer and telephone at the same time. There are two types of DSL: Asymmetric Digital Subscriber Line (ADSL) and Symmetric Digital Subscriber Line (SDSL).
Symmetric Digital Subscriber Line is similar to ADSL in that both use the existing copper wires of the traditional phone network. The major difference between these two types of DSL services is in their upload speed. SDSL offers equal bandwidths in both directions while ADSL delivers more bandwidth for downloading than uploading. This means that ADSL is preferable for most home users who browse the Internet and send e-mail but don’t need to upload large files or perform high-bandwidth data transfers.
Cable modem service works differently than DSL, as it uses coaxial cable instead of standard telephone lines. Because it uses cable television lines, cable modem service typically has a much wider bandwidth than DSL, typically between 3 and 10 Mbps downstream and 256 Kbps to 2Mbps upstream.
The Internet is a complicated and diverse place, but it’s essential that you be able to maintain an understanding of how it all works. Learning more about the various types of ISPs out there will help you determine which one is best for you, and equip you with critical information if something goes wrong. Fortunately, we’ve broken down this process as simple as possible. Use this information to continue to learn about the basics of the Internet so you can stay up-to-date on all things related. You’ll be glad that you did.