T568A and T568B Termination Standards

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• patch cords are terminated with RJ45 plugs
• structured cabling is terminated to insulation displacement connectors (IDC’s) in wall ports and distribution frames
• use a consistent wiring scheme across all sites

T568A and T568B

• The ANSI/TIA/EIA-568 standard defines two termination methods for twisted pair:
  • T568A
    • pin 1 is wired to green/white
    • pin 2 is wired to green
    • pin 3 is wired to orange/white
    • pin 6 is wired to orange
    • mandated by the residential cabling standard (TIA 570)
  • T568B
    • green and orange swap from T568A
    • orange pairs wire to pins 1 and 2
    • green pairs wire to pins 3 and 6
    • more widely deployed
• When cabling a network, best to use the same termination method consistently
  • A straight through Ethernet cable is wired with the same type of termination at both ends

Pin	Wire Color (T568A)	Wire Color (T568B)	10/100 Mbps	1/10/40 Gbps
1	Green/White	Orange/White	Tx+	BixA+
2	Green	Orange	Tx-	BixA-
3	Orange/White	Green/White	Rx+	BixB+
4	Blue	Blue		BixC+
5	Blue/White	Blue/White		BixC-
6	Orange	Green	Rx-	BixB-
7	Brown/White	Brown/White		BixD+
8	Brown	Brown		BixD-

Cat 7 and Cat 8

• Cat 7 and Cat 8 use a solid white as the second wire in a pair (no stripe)
• because they are very sensitive to noise
• the coloring process reduces effectiveness of insulation

Crossover Cables

Using T568A at one end and T568B at the other creates a crossover cable.

Crossover cables were once used to connect computers directly, but Gigabit Ethernet interfaces can perform the crossover automatically, even if standard cable is used.