3.1 - Network Cables

Question 1

The importance of cable

Answer 1

• Fundamental to network communication
  – Incredibly important foundation
• Usually only get one good opportunity at
  building your cabling infrastructure - Make it good!
• The vast majority of wireless communication uses cables
  – It has to plug in somewhere

Question 2

Twisted pair copper cabling

Answer 2

• Balanced pair operation
  – Two wires with equal and opposite signals
  – Transmit+, Transmit- / Receive+, Receive-
• The twist is the secret!
  – Keeps a single wire constantly moving
  away from the interference
  – The opposite signals are compared on the other end
• Pairs in the same cable have different twist rates

Question 3

Ethernet Cables Spec Table

Answer 3

Question 4

Coaxial cables

Answer 4

• Two or more forms share a common axis
• RG-6 used in television/digital cable
  – And high-speed Internet over cable

Question 5

Plenum-rated cable

Answer 5

• Traditional cable jacket - Polyvinyl chloride (PVC)
• Fire-rated cable jacket
  – Fluorinated ethylene polymer (FEP) or
  low-smoke polyvinyl chloride (PVC)
• Plenum-rated cable may not be as flexible
  – May not have the same bend radius
• Worst-case planning
  – Important concerns for any structure

Question 6

Unshielded and shielded cable

Answer 6

• UTP (Unshielded Twisted Pair)
  – No additional shielding
  – The most common twisted pair cabling
• STP (Shielded Twisted Pair)
  – Additional shielding protects against interference
  – Shield each pair and/or the overall cable
  – Requires the cable to be grounded
• Abbreviations
  – U = Unshielded
  – S = Braided shielding
  – F = Foil shielding
• (Overall cable) / (individual pairs)TP
  – Braided shielding around the entire cable and
  foil around the pairs is S/FTP
  – Foil around the cable and no shielding around
  the pairs is F/UTP

Question 7

Direct burial STP

Answer 7

• Overhead cable isn’t always a good option
  – Put the cable in the ground
• Provides protection from the elements
  – Designed to be waterproof
  – Often filled with gel to repel water
  – Conduit may not be needed
• Shielded twisted pair
  – Provides grounding, adds strength
  – Protects against signal interference