This document provides an overview of structured cabling and transmission media. It discusses different types of transmission media including twisted pair, coaxial cable, and optical fiber. It describes the characteristics of each medium and when each is typically used. It also covers structured cabling systems and the key subsystems including entrance facilities, equipment rooms, telecommunications rooms, backbone cabling, horizontal cabling, and work area components. The document compares backbone and horizontal cabling and provides examples of installing Ethernet cables.

1. Lesson 7
Structured Cabling
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2. 2
Transmission Media
Transmission medium: the physical path between transmitter and
receiver.
 Repeaters or amplifiers may be used to extend the length of
the medium.
 Communication of electromagnetic waves is guided or
unguided.
Guided media :: waves are guided along a physical path (e.g,
twisted pair, coaxial cable and optical fiber).
Unguided media:: means for transmitting but not guiding
electromagnetic waves (e.g., the atmosphere and outer
space).

3. 3
Transmission Media Choices
 Twisted pair
 Coaxial cable
 Optical fiber
 Wireless communications

4. Transmission Media - Aseel Alhadlaq 4
Digital Transmission Media Bit Rates

5. Twisted Pair
 Consists of two insulated copper wires arranged in a regular spiral
pattern to minimize the electromagnetic interference between
adjacent pairs
 Often used at customer facilities and also over distances to carry
voice as well as data communications
 Low frequency transmission medium
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6. 6
Twisted Pair
 Limited in distance, bandwidth and data rate
due to problems with attenuation,
interference and noise
 Issue: cross-talk due to interference from other
signals
 “shielding” wire (shielded twisted pair (STP)) with
metallic braid or sheathing reduces interference.
 “twisting” reduces crosstalk.

7. Types of Twisted Pair
 STP (shielded twisted pair)
 the pair is wrapped with metallic foil or braid to insulate
the pair from electromagnetic interference
 UTP (unshielded twisted pair)
 each wire is insulated with plastic wrap, but the pair is
encased in an outer covering
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8. Ratings of Twisted Pair
 Category 3 UTP
 data rates of up to 16mbps are achievable
 Category 5 UTP
 data rates of up to 100mbps are achievable
 more tightly twisted than Category 3 cables
 more expensive, but better performance
 STP
 More expensive, harder to work with
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9. UTP categories
Category 1 Voice only (Telephone)
Category 2 Data to 4 Mbps (Localtalk)
Category 3 Data to 10Mbps (Ethernet)
Category 4 Data to 20Mbps (Token ring)
Category 5
Category 5e
Data to 100Mbps (Fast Ethernet)
Data to 1000Mbps (Gigabit Ethernet)
Category 6 Data to 2500Mbps (Gigabit Ethernet)
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10. Twisted Pair Advantages
 Inexpensive and readily available
 Flexible and light weight
 Easy to work with and install
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11. Twisted Pair Disadvantages
 Susceptibility to interference and noise
 Attenuation problem
 For analog, repeaters needed every 5-6km
 For digital, repeaters needed every 2-3km
 Relatively low bandwidth (3000Hz)
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12. Coaxial Cable (or Coax)
 Used for cable television, LANs, telephony
 Has an inner conductor surrounded by a braided mesh
 Both conductors share a common center axial, hence
the term “co-axial”
 Traditionally used for LANs, but growth of twisted pair
for local nets and optical fiber for larger nets has
reduced coax use
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13. 13
Center
conductor
Dielectric
material
Braided
outer
conductor
Outer
cover
Coaxial Cable

14. 14
Coaxial Cable
 Divided into two basic categories for coax used in
LANs:
 50-ohm cable [baseband]
 75-ohm cable [broadband or single channel baseband]
 In general, coax has better noise immunity for
higher frequencies than twisted pair.
 Coaxial cable provides much higher bandwidth than
twisted pair.
 However, cable is ‘bulky’.

15. 15
Baseband Coax
 50-ohm cable is used exclusively for digital transmissions
 Uses Manchester encoding, geographical limit is a few
kilometers.
10Base5 Thick Ethernet :: thick (10 mm) coax
10 Mbps, 500 m. max segment length, 100 devices/segment,
awkward to handle and install.
10Base2 Thin Ethernet :: thin (5 mm) coax
10 Mbps, 185 m. max segment length, 30 devices/segment,
easier to handle, uses T-shaped connectors.

16. 16
Broadband Coax
 75-ohm cable (CATV system standard)
 Used for both analog and digital signaling.
 Analog signaling – frequencies up to 500 MHZ are
possible.
 For long-distance transmission of analog signals,
amplifiers are needed every few kilometers.

17. Fiber Optic Cable
 Thin (2 to 125 µm), flexible medium capable
of conducting an optical ray
 Advantages
 Greater capacity
 Smaller size/lighter weight
 Lower attenuation
 Electromagnetic isolation
 Attenuation in the fiber can be kept low by
controlling the impurities in the glass.
17

18. plastic jacket glass or plastic
cladding
fiber core
Fiber Optic Layers
 consists of three concentric sections
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19. 19
Optical Fiber
 Three standard wavelengths : 850 nanometers
(nm.), 1300 nm, 1500 nm.
 First-generation optical fiber :: 850 nm, 10’s
Mbps using LED (light-emitting diode) sources.
 Second and third generation optical fiber :: 1300
and 1500 nm using ILD (injection laser diode)
sources, gigabits/sec.

20. 20
Optical Fiber
 Attenuation loss is lower at higher wavelengths.
 There are two types of detectors used at the
receiving end to convert light into electrical energy
(photo diodes):
 PIN detectors – less expensive, less sensitive
 APD detectors
 ASK is commonly used to transmit digital data over
optical fiber {referred to as intensity modulation}.

21. 21
Optical Fiber
 Three techniques:
 Multimode step-index
 Multimode graded-index
 Single-mode step-index
 Presence of multiple paths  differences in delay
 optical rays interfere with each other.
 A narrow core can create a single direct path which
yields higher speeds.
 WDM (Wavelength Division Multiplexing) yields more
available capacity.

22. Fiber Optic Types
 multimode step-index fiber
 the reflective walls of the fiber move the
light pulses to the receiver
 multimode graded-index fiber
 acts to refract the light toward the center
of the fiber by variations in the density
 single mode fiber
 the light is guided down the center of an
extremely narrow core
22

23. fiber optic multimode
step-index
fiber optic multimode
graded-index
fiber optic single mode
Fiber Optic Signals
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24. Structured Cabling System
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25. Structured Cabling System
 Standards for cabling within a building (EIA/TIA-568 and
ISO 11801)
 Includes cabling for all applications, including LANs, voice,
video, etc
 Vendor and equipment independent
 Designed to encompass entire building, so that equipment
can be easily relocated
 Provides guidance for pre-installation in new buildings and
renovations
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26. Structured Cabling Subsystems
 Six subsystems:
1. Entrance Facilities are where the building interfaces with the outside
world.
2. Equipment Room: A room with equipment that serves the users inside
the building.
3. Telecommunications Room: This room contains the telecommunications
equipment that connects the backbone and horizontal cabling
subsystems.
4. Backbone Cabling: A system of cabling that connects the equipment
rooms and telecommunications rooms.
5. Horizontal Cabling: The system of cabling that connects
telecommunications rooms to individual outlets or work areas on the
floor.
6. Work Area Components: These connect end-user equipment to outlets of
the horizontal cabling system.
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27. 27

28. Backbone Cabling
 The backbone cabling is also called vertical cabling or
wiring.
 It provides interconnection between telecommunication
rooms, equipment rooms and entrance facilities.
 These backbone cablings typically are done from floor to
floor to floor.
 Cables: unshielded twisted-pair (UTP) cable, shielded
twisted-pair (STP) cable, fiber optic cable, or coaxial cable.
 Equipment should be connected by cables of no more than
30 meters.
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29. Horizontal Cabling
 The horizontal cabling system extends from the work area’s
telecommunications information outlet to the
telecommunications room.
 Horizontal cabling is usually installed in a star topology that
connects each work area to the telecommunications room.
 Cables: Twisted pair and fiber optic cable can be used for
horizontal cabling
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30. Horizontal Cabling
 To comply with EIA/TIA wiring standards, individual
cables should be limited to 90 meters in length between
the outlet in the work area and the patch panels in the
telecommunications room.
 Patch cords for connecting the patch panel to hubs and
switches in the telecommunications room should be no
longer than 6 meters total distance.
 Cables connecting users’ computers to outlets should be
limited to 3 meters in length.
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31. Horizontal Cabling
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32. Backbone vs Horizontal Cabling
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33. Backbone vs Horizontal Cabling
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1. The main difference between backbone cabling and horizontal cabling
is that they cover different telecommunication service areas.
 Backebone cabling is to connect the entrance facilities, equipment rooms
and telecommunication rooms.
 Horizontal cabling connects telecommunication rooms to individual
outlets on the floors.
 Backbone runs between floors. While horizontal is on one floor.
2. The cables used for backbone cabling have very different requirement
from the horizontal cabling:
 Backbone cables must meet particular fire-rating specifications.
 Backbone cable must have sufficient strength to support its own weight.
 Horizontal cabling system cable will be simpler.

34. Ethernet Cable
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35. Ethernet Cable
 The name, Ethernet Cable, always
refers to the following category:
 Category 5
 Category 5e
 Category 6
 Or more than those categories.
35

36. Ethernet Cable
 It is composed of 4-pair
twist wirings.
 Orange
 Green
 Blue
 Brown
Cat5e cable
http://www.cat5ecable.co.uk/
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37. Ethernet Cable
Color Pin (T568B)
White/Orange 1
Orange 2
White/Green 3
Blue 4
White/Blue 5
Green 6
White/Brown 7
Brown 8
• You can use the order of rainbow colors to
memorize the order of this wiring.
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38. Ethernet Cable
Pin Usage
1 Transmission (Tx+)
2 Transmission (Tx-)
3 Receive (Rx+)
4 --
5 --
6 Receive (Rx-)
7 --
8 --
• We can use the concept to justify the order of the wiring
colors of straight through and crossover.
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39. How to wire
 Prepare the materials and tools.
 Cable & RJ-45 plugs
 Scissors
 Crimping tool
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For RJ-45 plug.
Crimping tool

40. How to wire
 Strip off suitable length of the cable sheath.
 About 2-2.5 cm
 You can mark the position first.
40

41. How to wire
 Align the colored wires according to the specific order.
(Later we will talk about.)
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1 2 3 4 5 6 7 8

42. 42
Straight Through And Crossover Wiring
 Wiring within a twisted pair cable is configured as
either
 Straight through, where each wire (or pin) is attached
to the same contact point at each end
 Crossover, where transmit contacts on each end of the
cable are connected to the receive contact at the other
end

43. 43
Straight Through Wiring

44. 44
Crossover Wiring

45. 1→8
How to wire
 Straight Through
 All order of the wirings is the same as the other side.
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
45

46. Straight Through
Host A Host B
Pin Usage Color Color Usage Pin
1 Tx+ Tx+ 1
2 Tx- Tx- 2
3 Rx+ Rx+ 3
4 -- -- 4
5 -- -- 5
6 Rx- Rx- 6
7 -- -- 7
8 -- -- 8
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47. 1→8
How to wire
 Crossover
 We need to change the order of the transmission and
receiving wirings.
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
47

48. Crossover
Host A Host B
Pin Usage Color Color Usage Pin
1 Tx+ Tx+ 1
2 Tx- Tx- 2
3 Rx+ Rx+ 3
4 -- -- 4
5 -- -- 5
6 Rx- Rx- 6
7 -- -- 7
8 -- -- 8
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49. How to wire
 Trim all the wires to the same length.
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50. How to wire
 Insert the wires into the RJ45 plug.
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Transmission Media - Aseel Alhadlaq

51. How to wire
 Crimp the RJ45 plug with the crimping tool.
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52. How to wire
 Verify the order of the wires is correct and all the wires
are correctly making good contact with the metal
contacts in the RJ45 plug.
52
Incorrect
Correct

53. How to wire
 Cut the cable into suitable length and repeat the below
steps for the other side.
 Please be sure what kind of the cable you are wiring.
 Testing
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