Technical Support from PM-Systems


Most new Local Area Network (LAN) installations use either UTP (Unshielded Twisted Pair) or STP (Shielded Twisted Pair) Category 5 (CAT5) cable to wire either a 10Base-T or 100Base-T network topography. The following chart details the T568 standards for these networks. Professional Management Services normally uses the T568B connection standard for its 10Base-T and 100Base-T installations.

The TIA/EIA-568-A standard (IEEE 802.3) specifies two wiring schemes to be employed in Category 5 UTP/STP installations. The difference between the T568A and T568B schemes is that pairs 2 and 3 are reversed. Although 10Base-T only needs two pair, all four pairs must be terminated in either the T568A or T568B scheme. The T568B scheme is the most popular. The color scheme should be consistent throughout the system. The new 100Base-TX uses the same wiring scheme as 10Base-T (pairs 2 and 3) over Category 5 UTP.

UTP Color Codes
Pair 1 White-Blue (W-BL) Blue (BL)
Pair 2 White-Orange (W-O) Orange (O)
Pair 3 White-Green (W-G) Green (G)
Pair 4 White-Brown (W-BR) Brown (BR)
T568 Wiring
Courtesy of MilesTek

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This page last updated 7/20/99