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How Cable Modems Work - A Tutorial for Beginners

For the cable modem user and/or the curious researcher, we have an informative summary of how cable modems work, written in plain English.  Read on for an insightful overview.

To begin, a definition of cable modem is: a medium for transferring data to and from the Internet over cable TV lines.  There are two critical factors in a cable Internet connection. 

  1. The cable modem
  2. The cable modem termination system

Without either one of these, the cable connection would not be possible.  All information is transferred through the cable modem and the termination system. 

The cable modem is hooked up to the cable TV line in your home and to the computer.  It is responsible for transmitting upstream and downstream data back to the termination system.

The cable modem termination system is responsible for directing all traffic requests to the Internet service provider (ISP) for connection to the Internet.  All of this takes place in a matter of seconds.  

The Next Steps

Once you are connected to the Internet with your cable modem, the system places downstream data, or downloads into the equivalent of one channel of television programming.  Upstream data requires even less bandwidth.  With hundreds of channels available on the bandwidth of each cable line, cable has the potential to reach around 2 Mbps (with some providers offering up to 8 Mbps), giving it the possibility for the highest speed in broadband Internet.

Also, up to 1,000 users can be connected through a single channel, but when too many people are connected at a time, the connection speed can be slower than normal, averaging 1-1.5 Mbps.

More Useful Knowledge

Now that you know the basics of how cable modems work, consider yourself well-informed.  You might also be interested in the fact that cable Internet subscribers have one of the highest retention rates in the Internet service industry.  With a reliable and fast Internet connection that’s always on and ready to go, who wouldn’t be happy?