The information listed here is to assist Network Administrators in the color coding of Ethernet cables. RJ-45 conductor data cable contains 4 pairs of wires each consists of a solid colored wire and a strip of the same color. There are two wiring standards for RJ-45 wiring: T-568A and T-568B. Although there are 4 pairs of wires, 10BaseT/100BaseT Ethernet uses only 2 pairs: Orange and Green. The other two colors (blue and brown) may be used for a second Ethernet line or for phone connections. The two wiring standards are used to create a cross-over cable (T-568A on one end, and T-568B on the other end), or a straight-through cable (T-568B or T-568A on both ends). Please be aware that modifying Ethernet cables improperly may cause loss of network connectivity.
To create a straight-through cable, you have to wire T-568A or T-568B on both ends of the cable.
The TIA/EIA 568-A standard which was ratified in 1995, was replaced by the TIA/EIA 568-B standard in 2002 and has been updated since. Both standards define the T-568A and T-568B pin-outs for using Unshielded Twisted Pair cable and RJ-45 connectors for Ethernet connectivity. The standards and pin-out specification appear to be related and interchangeable, but are not the same and should not be used interchangeably. Both the T-568A and the T-568B standard Straight-Through cables are used most often as patch cords for your Ethernet connections.
The straight-through cables are used when connecting Data Terminating Equipment (DTE) to Data Communications Equipment (DCE), such as computers and routers to modems (gateways) or hubs (Ethernet Switches). The cross-over cables are used when connecting DTE to DTE, or DCE to DCE equipment; such as computer to computer, computer to router; or gateway to hub connections. The DTE equipment terminates the signal, while DCE equipment do not.
To create a cross-over cable, you have to wire T-568A on one end and T-568B on the other end of the cable.
To connect two computers without a hub, a cross-over cable is used. Cross-over cable is also used to connect a router to a computer, or ethernet switch (hub) to another ethernet switch without an uplink. Most ethernet switches today provide an uplink port, which prevents a use of cross-over cable to daisy chain another ethernet switch. Straight-through cables are used to connect a computer to an ethernet switch, or a router to an ethernet switch.
|RJ45 Pin Number Designations:There are pin number designations for each color in T-568B and T-568A.
Pin Color Pin Name Color Pin Name
--- ------------- -------- ------------- --------
1 Orange Stripe Tx+ Green Stripe Rx+
2 Orange Tx- Green Rx-
3 Green Stripe Rx+ Orange Stripe Tx+
4 Blue Not Used Blue Not Used
5 Blue Stripe Not Used Blue Stripe Not Used
6 Green Rx- Orange Tx-
7 Brown Stripe Not Used Brown Stripe Not Used
8 Brown Not Used Brown Not Used
RJ45 Color-Coded Scheme:
RJ45 cables have 8 color-coded wires, and the plugs have 8 pins and conductors. Eight wires are used as 4 pairs, each representing positive and negative polarity. The most commonly used wiring standard for 100baseT is T-586B stanrard described above. Prior to EIA 568A and 568B standards, the color-coded scheme was used to wire RJ45 cables. The table below depicts pin and color schemes used in traditional and standardized setup.
|Pin||Colored Scheme||T-568B (Common)||T-568A|
|1||Blue||Orange Stripe||Green Stripe|
|3||Black||Green Stripe||Orange Stripe|
|5||Green||Blue Stripe||Blue Stripe|
|7||Brown||Brown Stripe||Brown Stripe|
|8||White (or Grey)||Brown||Brown|
Filed Under: Ethernet
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