TIA/EIA-568

EIA/TIA-568A and EIA/TIA-568B are standards for the contacting of eight-pin RJ -45 plugs and sockets. They were defined by the three organizations Electronic Industries Alliance ( EIA), Telecommunications Industry Association (TIA) and International Telecommunications Union ( ITU). Both standards are in computer networks ( LAN) ( 10Base -T, 100Base -TX and 1000Base -T) used in Ethernet and in many digital telephone systems, which is EIA/TIA-568B used frequently.

The two variations are due to the fact that EIA / TIA much later than the AT & T introduced the TIA - 568A standard the proprietary standard 258A. As TIA - 568A was published, 258A was already widespread. EIA / TIA took over this already established standard therefore as TIA -568B.

Pairing and colors

A cable consists of eight individual wires. The eight wires are grouped by twisting two wires to four pairs of wires. The Twisting of the wires to reduce crosstalk to other pairs. The pairs must be used as such. If a cable wired incorrectly so that two wires of different pairs are used as a pair, is expected to errors in the computer network. In telephony, does it manifest itself as noise or crosstalk from other phone calls.

The wire pairs are colored in accordance with the first four entries of the 25 -pair color code table of AT & T, which are derived from the wiring of the 50 -pin ( 25 pair ) RJ -21 connector. The first strand is colored according to the primary color. Additionally there is a dash of secondary color available. The second vein is stained with the secondary color, and in addition with a dash of primary color. Depending on the manufacturer, the strokes can also extend transversely or eliminated to the veins.

The primary color of the first four entries is white. The secondary color of the first entry is blue, the second is orange, 3 is green, and the fourth entry is brown. Note that depending on the standard mapping of the contacts may be different.

Wiring

Regardless of the standard actually used the contacts of the RJ-45 plugs and jacks are numbered as follows:

This pin 1 of the connector pin 1 of the socket contacts. According to the standard used, the contacts are wired as follows:

The only difference between TIA - 568A and TIA -568B is the interchange of the pairs 2 and 3 (orange and green). Both standards wire the contacts "straight through". This means that the contact 1, on the one hand with the contact 1 at the other side is connected, and that is maintained at all the eight contacts. Whether the patch cable according to TIA - 568A or TIA -568B are placed is matter in this case since they are wired 1:1.

When cabling of networks is specified in the rule in advance whether is wired to TIA - 568A or TIA -568B and then implemented consistently. In Europe is generally according to TIA - 568A wired, as this assignment is consistent with the general color codes of the telephone installations. For historical reasons, however, TIA -568B is still quite common, especially in the USA, for new plants but usually take place there as well the TIA - 568A application.

If you connect a LAN cable to a plug according to TIA - 568A and the other plug according to TIA -568B, one obtains a crossover cable. The crossover cable is useful as a patch cable for point-to -point connections between two computers with 100BaseT or 10BaseT. ( From 1000BaseT is made the crossing from the network adapter automatically when needed. )