2. Starting in the Name of Allah,
The Most Beneficent, The Most Merciful

3. Channel
 A channel is a path between two
communication devices

4. Characteristics
 Signaling transmission method
 Medium used
 Bandwidth: amount of data transmitted
in a fixed amount of time
 Direction(s) in which signal can flow
 Noise, attenuation, and distortion
characteristics

5. Signaling transmission method
Analog: continuous varying waveforms
to carry data
Digital:
a.Two different values of electrical
voltage or current
b.On/off light source
c.Frequently preferred because less
susceptible to noise and interference

6. Directions
 Point to point channels
a. Simplex: channel passes data in one
direction only
b. Half-duplex: transmits data one direction
at a time (walkie-talkie)
c. Full-duplex: transmits data in both
directions simultaneously (telephone)

7. Channel Organization
 Multipoint: broadcasts messages to all
connected receivers larger number of recievers

8. Transmission medium
 Mediaz
Materials carrying the signal
a.Consists of two types:
i. Physical: wire cable
ii. Wireless: Air

9. Physical Transmission Media
 Twisted-pair cable
 Coaxial cable
 Fiber-optics

10. Twisted-pair cable
 Cabling is a type of wiring in which two
conductors of a single circuit are twisted
together for the purposes of canceling out
electromagnetic interference (EMI) from
external sources

11. Twisted-pair cable
c
twisted-pair cable
twisted-pair wire

12. Coaxial cable
 A type of cable that has an inner
conductor surrounded by a tubular
insulating layer, surrounded by a tubular
conducting shield. Many coaxial cables
also have an insulating outer sheath or
jacket.

14. Fiber-optics
 Its a flexible, transparent fiber made of
high quality glass (silica) or plastic,
slightly thicker than a human hair. It can
function as a waveguide, or “light
pipe”, to transmit light between the two
ends of the fiber

15. Fiber-optics

16. Fiber-optics
 Optical fibers are widely used in fiberoptic communications, which permits
transmission over longer distances and at
higher bandwidths (data rates) than other
forms of communication. Fibers are used
instead of metalwires because signals
travel along them with less loss and are
also
immune
to electromagnetic
interference.

17. Fiber-optics

18. Wireless Transmission Media

Broadcast Radio
a. Distribute signals through the
air over long distance
b. Uses an antenna
c. Typically for stationary
locations
d. Can be short range

19. Wireless Transmission Media
 Cellular Radio
a. A form of broadcast radio
used for mobile
communication
b. High frequency radio waves to
transmit voice or data

20. Wireless Transmission Media
 Microwaves
a. Radio waves providing high
speed transmission
b. They are point-to-point (can’t be
obstructed)
c. Used for satellite communication

21. Wireless Transmission Media
 Infrared (IR)
a. Wireless transmission media that
sends signals using infrared lightwaves

22. Wireless Transmission Media
 Infrared (IR)
a. Wireless transmission media that
sends signals using infrared lightwaves