3.1 Cables And Adapters: Copper Network Cables

Question 1

Importance of cables

Answer 1

Fundamental to network communocation

Get infrastructure right in the beginning or you will have issues

Question 2

Twisted pair copper cabling

Answer 2

Balanced pair operation

• two wires with equal and opposite signals
• transmit+, transmit- / receive+, receive-

Twist is secret
- because its twisting keeps a single wire constantly moving away from interference

Pairs in same cable have different twist rates

Question 3

Network cabling standards

Answer 3

Electronic industries alliance (EIA)

• develops standards for the industry
• standard starts with RS-# (recommended standard) or EIA#
• http://www.eia.org

Telecommunications industry association (TIA)

• standards, market analysis, trade shows, government affairs
• ANSI/TIA/EIA-568 - commercial building telecommunications cabling standard (standard thag is used when putting in cabling infrastructure)
• http://www.tiaonline.org

International ISO/IEC 11801 cabling standard
- defines classes of networking standards

Question 4

Cable catogories

Answer 4

Developed by organizations previously mentioned

Question 5

Non plenum

Answer 5

Air return space in the rafters is not open/circulating, it has a separate shaft to have forced air return (be taken out of the building)

Question 6

Plenum

Answer 6

Air return goes into the rafters, no separate shaft for it. This means air circulates in the same space that all the wires run.

• fire hazard
• need to have specific wires if going to run in plenum space to avoid hazard

Question 7

Plenum rated cables

Answer 7

Special cables used in plenum space

Traditional cable jacket (outside)

• polyvinyl chloride (PVC)
• dangerous because of their jacket, dont use in plenum space

Fire-rated cable jacket
- use in plenum space
- fluorinated ethylene polymer (FEP)
Or
- low smoke polyvinyl chloride (PVC)

Plenum rated not as flexible
- might not have same bend radius

Question 8

Unshielded and shielded cable

Answer 8

UTP (Unshielded Twisted Pair)

• no additional shielding after pvc coating
• most common twisted pair cabling

STP (shielded twisted pair)

• used in manufacturing or electrical environment
• adds additional shield from interference
• can shield each pair or overall cable
• requires cable to be grounded

Question 9

Shielded cable identifiers

Answer 9

Abbreviations
U = unshielded
S = braided shielding
F = foil shielding

Overall cable/ individual pairs

• S/FTP: braided shielding around entire cable and foil around the pairs
• F/UTP: foil around the cable and no shielding around the pairs

Question 10

T568A and T568B termination standard

Answer 10

Need to match wires to connect with correct pins for Ethernet

(Title) Standard for pins

Pin assignment comes from EIA/TIA-568-B standard
- aka: eight conductor 100 ohm balanced twisted- pair cabling standard

T568A and T568B are different pin assignments for 8P8C connectors
- assigns the T568A pin-out to horizontal cabling (same floor of building)

• many organizations traditionally use 568B (most important is to keep consistent
• don’t terminate one side with 568A and other with 568B
• this will cause issues (cant run ether at gigabyte speeds)

-

Question 11

TIA/EIA 568 A pin colors

Answer 11

1. white and green
2. green
3. White and orange
4. Blue
5. White and blue
6. Orange
7. White and brown
8. Brown

Question 12

TIA/EIA 568B pin colors

Answer 12

1. White and Orange
2. Orange
3. White and Green
4. Blue
5. White and Blue
6. Green
7. White and Brow
8. Brown

Question 13

Coaxial cable

Answer 13

Two or more forms share a common axis

Metal wire (conductor) running through center and encircled by different layers of stuff.

Types

RG- 6

• used in television/digital cable
• high speed internet over cable

RG - 56

• used to patch cables to other devices
• not good for long distance communication