Hardware Reference
In-Depth Information
the upfront cost by the number of months you plan to keep the service and add the result to the monthly
service charge to get an accurate figure.
Note
The examples in this section assume unlimited usage. If you use metered broadband (available
in some cable and many wireless data plans), be sure to add in the cost of any overages you
typically incur in a billing cycle.
For example, if cable modem service costs around $45 per month and has an average (not peak)
speed of 12Mbps, divide $45 by 12Mbps, and the cost is $3.75 per Mbps. The only extra equipment
generally required is a cable modem, which you can purchase for around $50 or rent for around $5
per month.
By comparison, the basic DSL service from AT&T costs around $20 per month (it can be as low as
$10 per month if you qualify for that rate) and has a speed of 0.768Mbps. Divide $20 by 0.768Mbps,
and the cost is $26 per Mbps, or only $13 per Mbps at the $10 rate. The only extra equipment
generally required is a DSL modem and some microfilters, which you can purchase for around $50 or
rent for around $5 per month.
How does a typical 56Kbps modem compare, assuming 50Kbps (0.05Mbps) download speeds?
Using the basic dial-up service from NetZero ($10 per month), the cost works out to $200 per Mbps.
That is 53 times more money per Mbps for service that is 240 times slower than a typical cable
modem.
The services offered in my area stack up as shown in
Table 16.2
,
listed from slowest to fastest
download speed.
Table 16.2. Comparing Connection Types and Speeds
Dial-Up Modems
In areas where broadband connections are not readily available, many people still rely on dial-up
modems. This section covers dial-up modems in detail.
The word
modem
(from modulator/demodulator) basically describes a device that converts the
digital data used by computers into analog signals suitable for transmission over a telephone line and
then converts the analog signals back into digital data at the destination. Because you must dial a
telephone number to reach a remote computer, these devices are also referred to as
dial-up modems
.
