Handout 1 Flashcards
act of transmitting and exchanging information between people, people and objects, and objects and objects through various media and actions
communication
has ultimate purpose of helping people communicate more efficiently and create better lives from it
communication
largest computer network in the world
internet
largest computer network in the world
internet
meaning of ARPAnet
Advanced Research Projects Agency Network
when was ARPAnet born
1989
refers to communication between terminal devices through a computer network
network communication
uses of signal
means of communication
communicated information
electronic transmitted information
this refers to a sign or indication that conveys information about something or that tells someone to do something
means of communication
refers to an event or act, which shows that something exists or that gives information about something
communicated information
refers to a detectable physical quantity or impulse (as a voltage, current, or magnetic field strength) by which messages or information can be transmitted via telegraphy, telephony, radio, radar, or television
electronic transmitted information
examples of signals
electrical signals
acoustic signals
video signals
biological signals
noise
signal that refers to voltages and currents in a circuit
electrical signals
signal that refers to audio or speech signals
acoustic signals
signal that refer to intensity variations in an image
video signals
signal that is interference/unwanted and undesired form of signal
noise
refer to disturbances in that energy to travel through a medium from one location to another
waves
refers to the horizontal distance of a wave from a point to the corresponding point on the next wave
wavelength
wavelength is measure in
meters (m)
refers to a vertical distance from a given point on the wave from the horizontal axis, it is the height above and below the x-axis
amplitude
amplitude is measured in
volts, amperes, or watts
it describes the position of the waveform relative to time zero; it relative to some fixed reference point or another sine wave.
phase
refers to the number of waves made per second or as cycles per second, it is the reciprocal of the period to complete one (1) wave cycle. The unit for frequency is in Hertz (Hz); 1 Hz means 1 cycle per second (cps).
frequency
refers to the amount of time (expressed in seconds) required to complete one (1) full cycle
period
general categories of waves
analog
digital
a wave in which both the amplitude and time continuously vary over their respective intervals that results in a wavy characteristic. Examples of this wave include the human voice and music.
analog wave
a wave with several discrete (jumpy) states, such as high or low, and on or off. It has fixed amplitude, but its pulse width and frequency can be changed. An example of this signal is the data stored in the memory of a computer in the form of Os and 1s.
digital wave
Computers facilitate information exchange and resource sharing from one location to another through some sort of wiring/cabling or waves that act as a physical path, which carries electrical or electromagnetic signals between a transmitter and a receiver
networking media
These networking media use cables and are limited by physical geography
wired or bounded media
media, these networking media cables in transmitting data and is not bounded by physical geography
wireless or unbounded media
transmission modes
simplex
half-duplex
full-duplex
a connection wherein data flows in one (1) direction only (unidirectional). This type is either transmit-only or receive-only
simplex mode
a connection wherein data can flow in both directions, but not simultaneously over a shared physical medium
half-duplex mode
is a connection wherein data simultaneously flows in both directions
full-duplex mode
is a transmission in which data with each bit lining up in a series as the bits are sent over a single wire at a time
serial transmission
a transmission wherein a group of bits is sent simultaneously, but each uses a different channel
parallel transmission
The most widely used standard for serial data communications is which is intended to operate over distances of up to 50 feet and has a communication speed that is equal to or less than 20Kbps
serial cable
refers to two (2) conductors enclosed by an insulating protective coating
coaxial cable
types of coaxial cable
thin (thinnet) cable
thick (thicknet) cable
it is a flexible coaxial cable about 0.25 inches thick. It uses British Naval Connector (BNC)-T cable connector attached to LAN Card (NIC)
thin (thinnet) cable
relatively rigid coaxial cable about 0.5 inches in diameter. It uses vampire top or piercing top as connectors.
thick (thicknet) cable)
consists of twe insulated strands of copper wire that are arranged in a regular spiral pattern.
twisted pair cable
refers to a twisted pair cable that contains no shielding.
unshielded twisted-pair cable (UTP)
It has eight (8) individual copper wires, in which pairs of them are twisted around each other
to form a four-pair color-coded wire medium that is encased in a flexible plastic sheath
UTP
refers to signal loss due to impedance
attenuation
refers to the twisted-wire pairs producing a magnetic field cancellation effect, which limits signal degradation caused by interference from nearby twisted pairs
crosstalk
refers to a twisted pair cable that combines the techniques of twisting wires, cancellation, and shielding
shielded twisted-pair cable (STP)
refers to a bundle of extremely thin and cylindrically shaped glass fibers surrounded by a concentric layer of glass coating that can conduct modulated light transmissions
fiber optic cable
parts of the fiber optics cable
core
cladding
coating
strengthening fibers
cable jacket (sheath)
refers to the innermost section that consists of one (1) or more very thin strands or fibers made of glass or plastic
core
refers to an outer optical glass or plastic coating that surrounds and traps the light in the core by the principle of total internal reflection
cladding
made from plastic that helps to shield the core and cladding from damage
coating
stand as protection for the core against compressive forces or crushing and tension or excessive pulling.
strengthening fibers
refers to an outermost layer that protects a buffer or a bundle of buffer- coated fibers against moisture, abrasion, crushing, and other environmental dangers.
cable jacket (sheath)
mode of fiber optic cable that allows light waves to travel along a single path or in only one mode. It is used for high-speed transmission over long distances. Multimode fiber optic cable: This fiber optic cable type allows light waves to travel
single-mode fiber optic cable
mode of fiber optic cable that allows light waves to travel into numerous paths through the core of the fiber at various angles. It is often applied to local area networks which encompass a much smaller transmission range
multimode fiber optic cable
refers to a wireless medium that is used for multicast communications (e. g. radio and TV ever long broadcasting, wireless local loop, mobile communications, and amateur radio) and paging systems distances
radio wave
also known as aerial, refers to a metallic structure that acts as a transducer that converts electrical energy to electromagnetic energy (upon transmission of signal) and vice-versa
antenna
types of wave propagation
line of sight propagation method
ground wave (surface) propagation method
skywave (ionospheric) propagation method
space wave (tropospheric) propagation method
a method by which radio waves travel from the transmitting antenna to the receiving antenna
line of sight propagation method
a method by which radio waves are radiated directly towards the earth’s surface.
ground wave (surface) propagation method
a method by which radio waves radiate upwards from the transmitting antenna of the earth into a direction towards the ionosphere
skywave (ionospheric) propagation method
method by which radio waves radiation exceeds 30 мна up to 300 GH
space wave (tropospheric) propagation method
to uled for sound/television broadcasting for ratio relay systems and for various mobile intein that operate at a frequency that ranges from 30 to 300 50, 300 AHz to 3 GHz, and 3 to G
space wave (tropospheric) propagation method
used for long distance radiotelephony and sound broadcasting with a frequency that ringes from 3 MH to 30 MH
skywave
refers to a wireless medium that is used for short-range communication (e. gremate control devices Intruder alarms, infra-red photography, and radiant heaters) in a closed area using line-of-sight propagation
infrared
refers to a wireless medium that is used for unicast communication such as wireless PAN (Bluetooth), broadband wireless access or wireless MAN (WIMAX), wireless WAN (2G/3G cellular networks). satellite networks and radar, and wireless LANS (Wi-Fi).
microwave
short-range wireless communication technology that allows devices such as mobile phones computers, and peripherals to transmit data or voice wirelessly over a short distance
bluetooth
