In general, I have found cable companies somewhat better at dealing
with customer service than are phone companies, although Ma Bell’s
deregulated descendants and competitors have improved their attitude
somewhat since comedian Lily Tomlin’s character Ernestine used to
snort, “We don’t care. We don’t have to. We’re the Phone Company.”
If your cable system is prone to regular outages or if you have had other
problems with the cable company, consider carefully whether you want
to give over your Internet connection to them.The cable between your home or office and the central office of the cable
company is shared by all users along the way; this is different from the
way most POTS wires are set up. This may or may not be a problem — it
depends on how many users are on your particular line and their usage
habits. It also depends on whether your cable company has upgraded to
more capacious fiber optics in your area. The only way to find out what
kind of service you will receive is to try it out; if you find the useable
speed too slow for your needs, ask the cable company for advice or con-
sider alternate communications methods.
The cable company should be able to deliver at least the minimum
speed it advertises.Cable modems, because they are constantly connected to the Internet,
are an attractive target for malicious hackers. Don’t even think about
using a cable modem without a hardware firewall(often built in to a
router) or a software firewall,or both. A firewall is a system, either hard-
ware or software, designed to prevent unauthorized access to your
system from external sources. And make sure that you install and keep
current a capable antivirus program.DSL modems .......................................................................................
I have previously described how POTS is limited to about 56,000 bps, or a bit
less depending on the age or capabilities of the phone company’s compo-
nents between your home or office and its destinations. But an alternative, a
system called Digital Subscriber Line (DSL),that is typically capable of speeds
of downloads as fast as 1.5 mbps in residential settings; that is about six or
seven times as fast as you’ll receive with a dial-up modem but still only a frac-
tion of the potential speed of a cable modem. Premium-service DSL offerings
promise download speeds of as much as 5 mbps. (Your results may vary,
faster or slower, depending on the quality of the wire in your area, the dis-
tance to the central office, and other factors.)
DSL takes advantage of the fact that POTS uses only a small slice of the avail-
able frequency range of copper wiring, sending analog voice signals in the
Chapter 15: Modems: The Essential Translators 231