Overview
This lecture explains Ethernet cabling standards, focusing on TIA/EIA 568A and 568B color schemes used for network installations.
Network Cabling Standards
- Networks between organizations follow strict installation standards for consistency.
- ISO/IEC 11801 is an international cabling standard.
- In North America, the TIA 568 standard (Commercial Building Telecommunications Cabling Standard) is widely used.
- Standards specify methods, pin assignments, and color codes for Ethernet cables.
T568A and T568B Pinouts
- T568A and T568B are parts of the TIA 568 standard detailing pin and pair assignments for 8-conductor twisted pair cables.
- Both standards describe which color wire connects to which pin in eight-position eight-conductor (8P8C) connectors like RJ45.
- 568A is commonly used for horizontal cabling; 568B is often used for end-user connections.
Differences Between 568A and 568B
- The main difference is the color arrangement for pins 1-2 (green/white-green in 568A, orange/white-orange in 568B).
- Pins 3 and 6 also swap orange and green between standards.
- Pins 4, 5, 7, and 8 (blue and brown wires) remain the same in both standards.
- Functionality is identical; choice depends on organizational preference.
Common Misconceptions
- 568A and 568B only define color codes, not crossover cables.
- Ethernet crossover cables are specified by IEEE standards, not by simply mixing 568A and 568B.
Identifying and Using Color Schemes
- Inspect the back of an Ethernet connector to identify which color standard is in use.
- Punchdown blocks often display both A and B color schemes for installer reference.
- Both standards assign blue and brown wires to the same pins, while green and orange wires change between A and B.
Key Terms & Definitions
- TIA 568 Standard — U.S. standard for structured cabling in commercial buildings.
- T568A / T568B — Wiring schemes specifying color codes for Ethernet cable pinouts.
- RJ45 (8P8C) Connector — Standard connector used for network cabling.
- Punchdown Block — Termination point for network cables, showing color codes for wiring.
Action Items / Next Steps
- Review the TIA 568 standard for more detailed information.
- Examine Ethernet cables and punchdown blocks to practice identifying color schemes.
- Prepare for future lessons on Ethernet crossover cables and IEEE pinouts.