Lecture on Fiber Optics and Cable Standards

Overview

• Importance of using the correct type of fiber optic connection.
• Differences between multimode and single-mode fiber.
• Copper cable types and standards set by TIA.

Fiber Optic Connections

Multimode Fiber

• Allows light to use multiple paths to travel.
• Fiber sizes: 50 Micron and 62.5 Micron.
• Total fiber with cladding: 125 Microns.

Single Mode Fiber

• Light uses a single path.
• Much smaller diameter: around 9 Microns.
• Total fiber with cladding: also 125 Microns.

Mixing Fibers

• Mixing single mode with multimode can cause signal errors.
• Color indicators are unreliable; documentation is critical.

Copper Cables and Standards

Cable Construction

• Regulated by the Telecommunications Industry Association (TIA).
• Cables are categorized (e.g., Category 5, Category 6, etc.).

Ethernet Standards

• Different standards require different minimum cable types.
• 1000Base-T: minimum Category 5.
• 10GBase-T: minimum Category 6 or 6A.
• Bandwidth and throughput differences.

Cable Testing

• Important to use cable testers to ensure proper installation.
• Testers can confirm category and detect errors like attenuation and CRC errors.

Cable Types and Interference

UTP vs. STP

• Unshielded Twisted Pair (UTP): No shielding, twisted pairs inside.
• Shielded Twisted Pair (STP): Shielded to reduce interference, includes grounding wire.

Cross Talk and Interference

• Cross Talk (XT): Signal interference within the same cable.
  • Near End Cross Talk (NEXT)
  • Far End Cross Talk (FEXT)
• Alien Cross Talk: Interference from other cables.
• Attenuation to Cross Talk Ratio (ACR): Comparison of signal loss to cross talk.

Installation Best Practices

• Maintain twists in the cable.
• Avoid electromagnetic interference (EMI).
  • Keep away from power cords, electrical systems, etc.
  • Use proper cable ties and avoid staples.

Attenuation and Cable Termination

Attenuation

• Loss of signal strength over distance.

Cable Termination

• Importance of correct termination to prevent performance issues.
• Mismatched pins can affect speed and connectivity.
• Auto MDI-X capability helps with incorrect pin connections.

Conclusion

• Correct fiber and cable installation is crucial for network performance.
• Regular testing and documentation are essential for troubleshooting and ensuring compliance with standards.