Chapter 3 Flashcards
What are the two categories of communications media.
- physical or conducted media
- radiated or wireless media
Conducted media includes what cables.
-Twisted pair wire
- Coaxial cable
- Fiber-optic cable
What cable comes as two or more pairs of single-conductor copper wires that have been twisted around each other.
twisted pair wire
What cable has 7 categories
Twisted pair wire
Why are the wires in twisted pair twisted.
It helps eliminate electromagnetic interface between the two wires.
the most common form of twisted pair; none of the wires in this form is wrapped with a metal foil or braid.
Unshielded twisted pair (UTP)
a form in which a shield is wrapped around each wire individually, around all the wires together, or both.
shielded twisted pair (STP)
a single wire (usually copper) wrapped in a foam insulation, surrounded by a braided metal shield, and then covered in a plastic jacket.
Coaxial cable
What are the two major coaxial cable technologies.
-Baseband
- Broadband
Which coaxial technology uses digital signaling in which the cable carries only one channel of digital
data.
Baseband
Which coaxial technology typically transmits analog signals and is
capable of supporting multiple channels of data simultaneously.
Broadband
the electronic distortion that a
signal passing through a metal wire experiences when a stray magnetic field passes over it.
Electromagnetic interference
a thin glass cable, a little thicker than a human hair, surrounded by a plastic coating.
Fiber-optic cable (or optical fiber)
Explain how a fiber-optic cable works
A photo diode or laser generates pulses of light which travel down the fiber optic cable and are received by a photo receptor
the main connecting cable that runs from one end of the installation to another
backbone
What transmission systems transmit tightly focused beams of radio signals from one ground-based microwave transmission antenna to another.
Terrestrial microwave
What are the two most common application areas of terrestrial microwave?
- Telephone communications
- Business intercommunications
Microwave transmissions do not what?
Microwave transmissions do not follow the curvature of the Earth, nor do they pass through solid objects.
What means that to receive and transmit a signal, each antenna must be in sight of the next antenna
line-of-sight transmission
Which transmission system signal travels from a ground station on Earth to a satellite and back to another ground station on Earth, thus achieving much greater distances than Earth-bound line-of-sight transmissions.
Satellite microwave transmission
What is a wireless technology that uses low-power, short-range radio frequencies to communicate between two or more devices.
The Bluetooth protocol
A small network like this with eight or fewer devices is called a what?
piconet
Multiple piconets can be interconnected form a what?
scatternet
What is a special form of radio transmission that uses a focused ray of light in the infrared frequency range (1012–1014 MHz)?
Infrared transmission
