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Physical Layer Technologies

Twisted pair cabling

  • Usually the one you have at home
  • Twisted pair categories
  • When a signals jump from a wire to wire, it's called crosstalk.
    • this is why they are twisted, to avoid crosstalk.
  • STP
    • Shielded Twisted Pair
  • UTP
    • Un-Shielded Twisted Pair

Connectors

Diffrent Cat Type cables.

Cat 1 Doorbell
Cat 2 Token Ring
Cat 3 Telephone / 10Mbps Ethernet
Cat 4 High Speed Token Ring
Cat 5 100Mb Ethernet
Cat 5e Gigabit Ethernet
Cat 6 Gigabit Ethernet

The plastic "core" you find in Cat 6 cables is working as a spacer for the cables, and is twisted in such a way that gives the best possible speeds for that cable.

EIA/TIA-568-B

  • Standard Cable
Pin Meaning Wire Color
1 Transmit + White/Orange
2 Transmit - Orange
3 Receive + White/Green
4 Blue
5 White/Blue
6 Receive - Green
7 White/Brown
8 Brown
  • Crossover Cable
  • When to use
    • Need to connect a
      • Switch to Switch
      • Router to Router
      • PC to PC
        • But it's not needed now as it's not needed with newer gear.
           1
           2
           3
           4
           5
           6
           7
           8
           9
          10
          11
          12
          13
                568-B                   568-A
             ------------             ---------
              TX + 1 W/O              TX 1 G/O
              TX - 2 O                TX 2 G
          
              RX + 3 W/G              RX 3 W/O
              RX   4 BL               RX 4 BL
          
              RX   5 W/BL             RX 5 BL/O
              RX - 6 G                RX 6 O
          
              ??   7 W/BR             ?? 7 W/BR
              ??   8 BR               ?? 8 BR
          

Coaxial cabling

  • Cable TV / Cable Internet
    • RG-6
    • F-type connector
  • Antenna connections
    • LMR-200, LMR-400, LMR-900
    • MANY connector

Serial cabling

  • V.35 cables
    • Several connector types
  • DS1 Cable
    • Twisted pari cable
    • RJ-45

proprietary cabling

Fiber Optics

  • SPF - Small Pluggable Formfactor
  • Single mode Fiber
    • LX (long haul) Laser
    • Distance: 70 km
  • Multi mode Fiber
    • SX (short haul) Laser
    • Distance: 1/2-1 km
  • Connector Types
    • ST connector
    • SC connector
    • LC connector (most used)

Wireless Ethernet

  • 802.11
    • Spectrum
      • 2.4 Ghz
        • Channels
          • Each channel is 22 MHz apart.
          • Start: 1 - 2.4000 Ghz
          • Stop: 14 - 2.499 Ghz
      • 5 Ghz
        • Channels
          • Start: 36 - 5.180 GHz
          • Stop: 161 - 5.835 GHz
          • DFS - Dynamic Frequency Selection