Signals are usually transmitted over some transmission media that
are broadly classified in to two categories.
a) Guided Media:
These are those that provide a conduit from one device to another
that include twisted-pair, coaxial cable and fiber-optic cable. A signal
traveling along any of these media is directed and is contained by the physical
limits of the medium. Twisted-pair and coaxial cable use metallic that accept
and transport signals in the form of electrical current. Optical fiber is a
glass or plastic cable that accepts and transports signals in the form of
light.
b)
Unguided Media:
This is the wireless media that transport electromagnetic waves
without using a physical conductor. Signals are broadcast either through air.
This is done through radio communication, satellite communication and cellular
telephony.
No comments:
Post a Comment