Cable Modem Guide By Bruce Stewart,
To If you're lucky enough to get cable modem access, find out how
to configure your PC, get online resources and stay connected to
If you have a slow modem, you've probably felt the urge to pull
your hair out while waiting for Web pages to load. Fortunately,
there's good news on the Internet connection speed front: A way
to get high speed (really, really fast), low cost (we're talkin'
$40 a month here), and easy installation(someone else does it all
for you) does exist. You're probably screaming "SIGN ME UP NOW!"
But that's where the catch is.
Cable modems are still somewhere over the rainbow for many of us,
but for a growing number of Web surfers, fantasy has become a reality.
If you're one of the lucky few who can get your Internet connection
from your cable TV provider--congratulations! This article's for
We'll take a look at the basic concepts involved in high-speed
cable modem access to the Net, describe the steps involved in setting
up your system, and give you plenty of online resources for the
Bruce Stewart is a freelance technology writer. He covers Web software,
operating systems, the wireless industry and contributes regularly
Currently about 67 million U.S. households get cable TV service.
The same wire that brings this signal into your home is capable
of providing Internet access at speeds that dwarf current dial-up
modems. The cable companies are in the process of installing and
upgrading equipment to offer this service, and now you might have
this option in your neighborhood.
Comparing the current ways consumers can connect to the Internet
from their home, cable access comes out looking pretty attractive.
At roughly the same cost of dial-up access with a dedicated telephone
line, and cheaper than ISDN or most DSL services, cable modem connections
will have those Web sites on your computer screen in the blink of
If you have a dedicated modem line and one of the latest modems,
you are probably paying between $35 and $45 per month for dial-up
Internet access at speeds up to 56kbps (phone line plus ISP). If
you're using ISDN, you can expect to pay between $70 and $100 per
month for speeds up to 128kbps, and DSL users will pay a similar
amount for speeds up to 384kbps. But if you can get Internet access
from your cable company, expect to pay around $40 per month for
unlimited, "always connected" access at speeds up to 10Mbps (that's
A cable modem is a device that connects to your existing cable
feed and to an Ethernet network card in your PC (also called a "NIC,"
Network Interface Card). A cable modem is a true modem--MO for modulates
and DEM for demodulates--but it is a much different device than
common dial-up modems.
A dial-up modem may be an internal or external device, and connects
to a serial port on your computer at a maximum speed of 56kbps.
Today's cable modems are external devices that connect to a network
card in your computer, and support much higher speeds than dial-up
devices. In addition, the cable modem you need to use is determined
by your cable company. While there are many manufacturers making
cable modems, Motorola has the largest market share.
Initially, there were no standards, and the different cable modems
could not talk to each other. Then, the industry came together and
agreed on the Data Over Cable Service Interface Specification (DOCSIS)
standard. This allows third-party vendors to make compliant cable
modems, and resulted in lower equipment costs. DOCSIS recently became
the CableLabs Certified Cable Modem project, which continues to
certify cable modem equipment. In all cases, the other end of the
cable modem connects to an Ethernet network card in your computer.
The cable TV network and the coaxial cable that brings it into
your home or office are capable of very high data transmission rates.
Some cable networks claim speeds up to 36Mbps, but practically speaking,
the top speed a modern PC with an Ethernet card can support is 10Mbps.
The cable network is designed to support the highest speeds in
the "downstream" direction, which is from the Internet to your computer.
This downstream speed affects the performance of downloading Web
pages and software. The "upstream" bandwidth--the data sent from
your computer to the Internet (mainly mouse clicks and e-mail messages)--is
typically less, in the range of 200kbps to 2Mbps.
At this time, you're lucky if this service is offered where you
live. Approximately 20% of U.S. households with cable TV currently
have the option for cable modem Internet access, though Kinetics
predicts over 80 per cent of cable homes will have the option by
the end of 2003. Of the approximately 40 million households that
have online connections, less than 10% of these have what can be
considered high-speed access, which includes both cable modems and
Some areas have experienced early implementation of this technology--California,
New York, Virginia, and Las Vegas, just to name a few. A general
list of the current commercial cable modem launches in North America
can be found at the Cable
Modem Info Center.
If you think you might be able to get Internet access, the only
sure way to know is to ask your local cable company. Some of the
larger providers have Web sites with zip code lookups, but this
will only tell you if that specific cable company offers this access
in your area. Since any given neighborhood has only one cable TV
provider, you need to identify your local provider, and contact
them for more information. You will most likely be told that Internet
access is planned for the near future, and possibly be given a time
frame. With luck, though, your cable company could tell you they
offer this service now and you can sign up on the spot.
Most modern home computers can be equipped to use a cable modem.
Cable modems connect differently to your computer than standard
dial-up modems though; you'll need an additional network card, which
the cable companies who offer Internet access usually provide. In
addition, your computer must have an available slot for the Ethernet
The basic requirements for a system to work with today's cable
modems are either a PC with at least a 66MHz 486 processor or a
Macintosh with at least a 68040 processor, and 16MB of memory. Of
course performance will improve with faster processors and more
RAM on either platform. The Road Runner service recommends 32MB
of RAM and a 166MHz Pentium or 250MHz PowerMac.
Getting started with cable modem Internet access is quite a bit
different than with a regular dial-up ISP. In most cases, when you
subscribe to Internet access from a cable provider they send a technician
to install the cable modem and verify the quality of your cable.
The cable technician will install a splitter onto your existing
cable, which allows you to connect to the Internet while still using
this wire for your cable TV access as well. There is no problem
using the Internet connection and watching cable TV at the same
time. A cable modem will be installed on the coax cable at an outlet
near your computer.
The cable company will also arrange for the installation of the
network card in your PC, if it does not already have one. You may
be asked to take your computer to a repair shop authorized by your
cable company to do this installation. Or, you may even decide to
do it yourself if you're comfortable opening up your computer and
installing a card.
Whatever the specific arrangements your cable company makes with
you, rest assured they will be much more involved in setting up
your connection than a standard dial-up Internet service provider.
Gone are the days of getting sent some software you are expected
to install, or given cryptic configuration information over the
phone you need to enter into your computer. Instead, the cable company
will visit your house and install your modem, check your wiring,
and arrange for a technician to install your network card and configure
While the speeds and costs associated with cable modem access seem
almost too good to be true, there are potential downsides to cable
modem technology. With the cable TV network, your computer is essentially
being put on a Local Area Network (LAN) with other users in your
neighborhood, and this presents a couple of possible problems.
Performance Like any LAN, the performance degrades as usage increases.
It's a fact that other users on your street, and probably beyond,
share the same data "pipe" you are using. So if everyone is downloading
at the same time, your performance will suffer; nevertheless, cable
networks claim to offer downstream speeds greater than any other
option, even under worst-case scenarios of high neighborhood usage.
As this type of access grows in popularity, the cable companies
may not be able to maintain the same speed and level of service
they can now provide.
Potential downsides While the speeds and costs associated with
cable modem access seem almost too good to be true, there are potential
downsides to cable modem technology. With the cable TV network,
your computer is essentially being put on a Local Area Network (LAN)
with other users in your neighborhood, and this presents a couple
of possible problems. Performance Like any LAN, the performance
degrades as usage increases. It's a fact that other users on your
street, and probably beyond, share the same data "pipe" you are
using. So if everyone is downloading at the same time, your performance
will suffer; nevertheless, cable networks claim to offer downstream
speeds greater than any other option, even under worst-case scenarios
of high neighborhood usage. As this type of access grows in popularity,
the cable companies may not be able to maintain the same speed and
level of service they can now provide. Network security Perhaps
a more disturbing issue is that of network security. One of the
main purposes of a LAN is to allow file sharing among the computers
on the LAN. This LAN feature doesn't work well with cable Internet
access however, as you probably don't want your neighbors accessing
There have been widely reported incidents of this type of breach,
where a cable modem user can access files on another user's computer
in his neighborhood who inadvertently had their file sharing settings
turned on. To be on the safe side, you should make sure you don't
have file sharing allowed on your computer if you are going to get
cable modem access.
To disable file sharing on PCs running Windows 95, 98, and Me,
go to the Network Control Panel and click on the Configuration tab.
Click on "File and Print Sharing" in the lower part of the window,
and make sure the button by "I want to be able to give others access
to my files" is not selected. Click "OK" twice, and your files will
not be visible to anyone else who happens to be on the same LAN
To disable file sharing on a Macintosh, go to the Sharing Setup
Control Panel and look for the File Sharing section. If you see
"File Sharing is Off" and a button marked "Start," your files cannot
be accessed. If, however, you see a button marked "Stop" you should
click on it. You will then be prompted for how many minutes the
computer should wait until it turns file sharing off. Pick a number
and click "OK," so that your files will no longer be accessible.
High growth is expected in this industry from all corners, especially
in the next several years. Dataquest estimates that cable modem
subscribers will grow from 3.3 million to 14 million by 2004. IDC
forecasts that cable modem service revenues will rise from $421.9
million in 1999 to $26 billion by 2003.
There has been a significant investment in infrastructure. The
National Cable Television Association reports cable operators will
spend $33 billion before the end of this year to upgrade their systems
to deliver fast Internet access
In addition to allowing for smoother Web surfing, cable modem's
high speeds and constant connection are facilitating other new interactive
applications that couldn't exist in dial-up settings. Just think,
the near future may offer video e-mail and subscriptions to CD-ROM
libraries. These libraries will offer the same level of interactivity
as if the CD-ROM were being played on your local computer.
The bottom line is that today, cable modems provide high access
speeds and lower prices than most other methods of connecting to
the Internet. While availability is still rather limited, this is
changing rapidly. You can expect the Internet coming to a cable
TV system near you very soon.
@Home Network www.home.com
Road Runner Service www.rr.com
AT&T Broadband www.broadband.att.com
Motorola CableComm Products www.mot.com/MIMS/Multimedia/
Cable Modem Info Center cabledatacomnews.com/cmic.htm
CATV CyberLab www.catv.org
Cable Modem Resources on the Web