The Internet, a Cable Modem and You

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Cable Modem

If you want a High Speed Internet connection for your home, you have several options — an Asymmetric Digital Subscriber Line (ADSL) using a phone line, a Cable Modem, or what’s known as Fiber to the X (FTTX), which uses a mix of fiber optic and copper cables.

Each type offers a number of benefits and drawbacks, but of the three, cable-based Internet is often considered the most versatile. So how does it work?

Calling All Cable Companies

It starts at your cable company — the same place that provides your Cable TV can also offer Internet services, and through the same kind of cord that runs to your television. This kind of cord is known as a coaxial cable and is easily identified by the small bit of copper wire that protrudes at both ends.

It must be properly seated in your TV’s coaxial jack, as well, as a wall jack to deliver a consistent signal. Invented over 130 years ago, this type of cable easily carries audio and video transmissions. It comes in many types for different applications, but the type most commonly used in homes is known as “RG-6.”

Cable television signals are sent along the coaxial cable’s available electrical “space,” also known as “bandwidth.” Each TV channel takes up about 6-megahertz (MHz) of bandwidth out of an available 1000 MHz, meaning there is plenty of extra space — space that can be used to carry an Internet signal.

Swimming Downstream

In order to use your cable provider’s Internet, you’ll need a standard RG-6 cable, a cable modem and a computer. In some cases, these modems are an internal part of desktop computers, but it is more common to see them externally, as something either sold or rented by the cable company.

Once hooked up to a computer and wall jack, the RG-6 cable uses a 6 MHz slice of bandwidth to send all necessary “downstream” data. This includes information going from the Internet to your computer, like websites, videos or documents you want to access. But it only needs a 2 MHz piece of bandwidth to send anything upstream, or out from your computer, like emails or photos.

By making use of otherwise empty bandwidth space on your television’s cable cord, providers can offer a way to get both Cable TV and High Speed Internet from a single source. But this would be without the need for specialĀ adapterĀ jacks, as when a phone line is used to transmit Internet data.

Inside Your Cable Modem

While it shouldn’t ever be necessary for you to tinker around inside your cable modem, it’s worth knowing the basics of what goes on when a signal is received. First, the signal will be received by a tuner, which may separate TV channels from those used by the Internet, and may also specify which set of frequencies are for upstream and downstream data movement.

Next, the signal moves to the modem’s demodulator, which takes the radio signal carried on the coaxial cable and turns it into simpler version ready for processing by an analog-to-digital (A/D) converter. This converter turns the signal into a series of 1s and 0s, also known as Binary Code, and then the signal gets checked for errors.

A device known as a MAC then takes the altered signal and interfaces with your computer’s central processing unit (CPU). The CPU sends out the signal to various parts of your computer, allowing you to view websites on your monitor, download movies or songs and store them either on your hard drive or on a portable device like a USB drive.

Going the other direction, your modem works in reverse, but just before the signal from your computer gets to the tuner, it runs through a modulator, which turns it back into a radio signal. It is then sent to your cable provider’s Modem Termination System and routed to an Internet Service Provider (ISP).

Who Uses Cable?

According to a 2011 study at Point Topic, an Internet use analysis firm, the rate of Cable Internet adoption is growing steadily, with 20 percent of users worldwide choosing this type of high-speed access. That comes out to over 100 million users, with half of those located within the United States. In part, this is thanks to the large number of cable providers in the U.S., many of which have robust Cable TV and now High Speed Internet networks. Most will offer a “bundle” deal if customers choose to buy both television and Internet services, and can typically match the speeds of competing technologies, such as ADSL or FTTX.

If you’re looking for a reliable way to access the Internet without the need for special wall jacks and extra cords, or you simply want to bundle your services with a Cable TV provider, consider the use of a cable modem. Click here to see which Internet providers are in your area and what special deals they are currently offering.

1 COMMENT

  1. Doug,
    This is Marcos from Mexico. I have a dumb question maybe. How does the internet + tv signal work? does it need an special router? I am thinking in build a small company that provides internet. We already have the cable company but I wonder if you know how to add the Internet feature.What devices? costs? etc..

    Regards,
    Marcos

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