Lecture Notes on Copper Cabling in Ethernet Networks

Introduction

• Copper cabling is the foundation of Ethernet networks.
• Commonly used in home networks.
• Important to choose the correct type of cable for the network being installed.

Structure of Twisted Pair Ethernet Cables

• Inside a twisted pair Ethernet cable:
  • Four pairs of wires, twisted around each other.
  • Pairs send equal and opposite signals (transmit plus/minus, receive plus/minus).
• Twisting helps mitigate noise and interference, allowing for signal reconstruction at the receiving end.
• Different pairs have different twist rates to aid in signal integrity.

Categories of Twisted Pair Cables

• Category 5 (Cat 5): No longer commonly used.
• Category 5e (Cat 5e): Enhanced version, supports 1000Base-T up to 100 meters.
• Category 6 (Cat 6): Supports 10GBase-T up to 55 meters (unshielded) and 100 meters (shielded).
• Category 6a (Cat 6a): Augmented version, supports 10GBase-T up to 100 meters.
• Category 7 (Cat 7): Shielded, supports 10GBase-T up to 100 meters.
• Category 8 (Cat 8): Shielded, supports 40GBase-T up to 30 meters.

Coaxial and Twinaxial Cables

• Coaxial Cable: Used for cable modem connectivity, TV, and digital internet connections (e.g., RG6).
• Twinaxial Cable (Twinax): Similar to coaxial but with two conductors; used for 10G Ethernet over copper (short distances, low cost, low latency).

Cabling Standards

• ISO/IEC 11801: International standards for structured cabling.
• TIA Standards: Common in North America, specifically ANSI/TIA-568 standard for commercial building telecommunications cabling.
• TIA-568 Standards: Focus on pin and pair assignments for 8-conductor, 100-ohm balanced twisted pair cables.
  • T568A and T568B standards dictate color codes for Ethernet cables.
  • T568A and T568B use different color codes but ensure compatibility if used consistently.

T568A vs T568B

• T568A: Common for horizontal cabling.
• T568B: Preferred by many organizations.
• Important to use the same standard on both ends of the cable to avoid confusion and functionality issues.
• Not related to Ethernet crossover cables (defined by IEEE 802.3 standard).

Color Codes for T568A and T568B

• T568A:
  • Pins 1 and 2: White/Green, Green
  • Pins 3 and 6: White/Orange, Orange
  • Pins 4 and 5: Blue, White/Blue
  • Pins 7 and 8: Brown, White/Brown
• T568B:
  • Pins 1 and 2: White/Orange, Orange
  • Pins 3 and 6: White/Green, Green
  • Pins 4 and 5: Blue, White/Blue
  • Pins 7 and 8: Brown, White/Brown

Practical Exercise

• Examine an Ethernet cable to identify whether it is wired to the T568A or T568B standard by checking the color of the wires at the connector.