Wired transmission media - Brookdale Community College

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Nov 21, 2013 (3 years and 9 months ago)

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Chapter 3

Wired & Wireless Communication

1

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Moving Data:

Bandwidth and Modems


Data is transmitted through:


Analog signals



Continuous waveforms


Used by telephones


Digital signals


Discontinuous pulses.


Used by computers

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2

Moving Data:

Bandwidth and Modems

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3

Moving Data:

Bandwidth and Modems


Bandwidth
-

maximum amount of data
transmitted through a communication
channel


Measured in Bits per Second (bps)


Broadband


transmits large amounts of data at high
speeds (> 1Mbps)


More expensive than dial
-
up

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4

Moving Data:

Bandwidth and Modems


Modem
-
Communication device
transmits data over telephone lines.


Short for Modulate/Demodulate

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5

Moving Data:

Bandwidth and Modems


Modulation



transforms digital signals
into analog signals.


Demodulation

-

transforms analog
signals into digital signals.

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6

Wired and Wireless
Transmission Media


Wired transmission media


Uses solid forms


twisted
-
pair, coaxial, and fiber
-
optic cables


Wireless transmission media


Sends data through the air


Infrared, radio, microwave signals.

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7

Wired and Wireless
Transmission Media

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8


Twisted
-
pair cables


Four twisted wires


Slowest


For telephone


Coaxial cables


Copper wire surrounded by
insulation


Cable TV


Wired and Wireless
Transmission Media


Fiber
-
optic cable


Thin strands of glass or
plastic that carry data
through pulses of light.


Fiber Optic


Infrared


Wireless transmission
uses light beams through
the air.


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9

Wired and Wireless
Transmission Media


Bluetooth


Short
-
range radio transmission


Within 30 feet

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10

Wired and Wireless
Transmission Media


Microwaves



High
-
frequency radio waves


Satellites



Stations in space that
transmit data through
microwave signals to and
from Earth
-
based stations.


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11

Wired Communication via the
Public Switched Telephone
Network


Digital Subscriber Line (DSL)

high
-
speed access to the Internet.


More expensive than dial
-
up


Less expensive than cable, FiOS


Requires


Modem


Telephone Line


Subscription

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12

Convergence: Is It a Phone or
a Computer?


Cellular telephones


Originally analog devices, are digital
devices that use radio signals to transmit
voice, image, text, and video data.




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13

Convergence: Is It a Phone or
a Computer?


Digital cellular technologies use
convergence to make
smartphones
,
which combine the features of phones
and computing devices.

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14

Wired and Wireless
Applications


Internet telephony,
aka

VoIP
(Voice over Internet Protocol)
, uses
the Internet for real
-
time voice
communication.

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15

Wired and Wireless
Applications

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16



Videoconferencing

transmits sound and
video images to people in different
locations through digital video technology.

Wired and Wireless
Applications


Global Positioning System (GPS)


System of 27 satellites that interact to allow
users to obtain driving directions




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17

Wired and Wireless
Applications


Text messaging


Instant messages
through a cellular
telephone


Texting While Driving

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18

Wired and Wireless
Applications


Picture messaging

is the transmission
of color pictures and backgrounds. The
cellular telephone acts as a camera.


Sexting


Sexting Suicide



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