The cabling most often used in local-area networks (LANs) is twisted
pair. In a typical home application, we use twisted-pair cable to
connect a personal computer's Ethernet card to a router, a hub, or a
DSL modem. As the name suggests, this kind of cable is made of two
wires twisted around each another. The wires are independently
insulated but also enclused in a single plastic sheath.
webopedia.com: twisted-pair cable
http://www.webopedia.com/TERM/T/twisted_pair_cable.html
Coaxial cabling, or coax, is more expensive than twisted pair, but has
a much higher data capacity. Coax consists of a single strand wrapped
in an insulating plastic sheath and shielded by a layer of braided
wire, which, in turn, is surrounded by dense rubber. Coax is the kind
of cable used to carry cable-television signals, and is also applied
to some extent in computer networking.
webopedia.com: coaxial cable
http://www.webopedia.com/TERM/C/coaxial_cable.html
The third most popular kind of cable, called fiber-optic, is today
used chiefly in Internet backbone lines and other long-range,
ultra-high-bandwidth applications. Fiber-optic cable is expensive, as
are the optical switches required to build networks with it, but costs
are gradually dropping as more businesses choose fiber optics to meet
the needs of their increasingly bandwidth-intensive applications.
Fiber-optic cable consists of thin glass or plastic strands that each
carry an independent set of signals, which are transmitted directly in
digital form by a series of light impulses.
webopedia.com: fiber optics
http://www.webopedia.com/TERM/F/fiber_optics.html
High-security applications call for fiber-optic cable, since it is
extremely resistant to wire-tapping. In the case of metallic cabling,
such as twisted pair, coax, and ordinary telephone wire, the signal
can be intercepted by holding a copper coil near the cable. Through
the physical process of induction, the coil will pick up all signals
passing through the target wire.
The principle of induction doesn't apply to fiber optics, where
signals are transmitted not by an electrical current, but by a beam of
light. Although it is possible to install a splitter on a fiber-optic
line, this requires cutting the wire at some point, which interrupts
the signal and is therefore easily detected. This makes fiber-optic
cabling the clear choice when security is the prime criterion.
newsfactor.com: Fiber Optics vs. Gigabit Ethernet
http://www.newsfactor.com/perl/story/19898.html
Queries used:
twisted pair
twisted-pair cable
coax
coaxial
fiber optics
fiber-optic cable
Cheers,
leapinglizard |
