Media (pg. 2)
Copper vs. Fiber Optic Cable
The termination, components, and connector costs are much higher than for copper wiring,
since specialized equipment is required to terminate fiber cables within buildings, to
test and splice fiber, and to convert electrical signals to light pulses. Specialized
technicians, who may be paid at higher levels, are also often required to work with and
test fiber cabling. When fiber is brought into buildings from telephone companies or to
the curb in residential areas, local electrical power is needed, leading to extra expense.
More care in handling the fiber is needed, and in particular, the fiber is not as flexible
as twisted pair in bending around corners.
Despite the disadvantages, the advantages have many communication companies replacing
their copper cabling with fiber-optic cables. The added expense of fiber, they feel, is
justified because of the greater capacity and speeds. In addition, telephone companies
need only lay a few strands of fiber to achieve the same capacity as heavier copper
cables. Moreover, signals can travel further in the range of 30 miles on fiber without the
use of repeaters to strengthen a faded signal, and as such, fewer repeaters are needed.
This translates into lower maintenance cost.
Technical improvements, such as ever-purer glass fibers and new methods of feeding light
pulses into the fibers, have produced constant increases in the carrying capacity of
fiber-optics systems. A fiber-optic cable laid under the Atlantic Ocean in the 1990s by
AT&T transmits 5 billion bits per second over each of 2 pairs of fibers enough
for 320,000 simultaneous conversations.
In the 1980s, US
companies started laying fiber-optic cable in earnest. By 1994, the nation was
criss-crossed by an optical fiber network. But since it costs too much, the last mile or
so uses copper cables. For example, its similar to a 6-lane highway that links
cities and towns, while local traffic still use normal roads.
Another medium being discussed for in-building local area networks (LAN) is wireless
communication. Wireless has advantages in the mobility it provides. Wireless LAN
connections are less messy - it enables computers to move and office space to be
reconfigured without LAN administrators having to physically move cabling. It also carries
data at higher speeds than any other media at 100 megabits and greater.
However, wireless, like fiber optics, involves a much higher cost as compared to
unshielded twisted pair and has the added problem of interference in some office
environments. For example, wireless cannot travel through 1-foot thick walls, since that
thickness impedes data from traveling through them.
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Fiber Optic Cable
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