Ethernet 100Base-T4

RJ-45 (8P8C) pinout for 100BASE-T4 Fast Ethernet, which runs 100 Mbit/s over all four pairs of Category 3 cable.

Updated:

thumb|right|240px|8P8C modular plug pin positioning

RJ45 FEMALE CONNECTOR 8 pin RJ45 (8P8C) female connector at the network interface cards/hubs.

RJ45 MALE CONNECTOR 8 pin RJ45 (8P8C) male connector at the cables.

100BASE-T4 is an early form of Fast Ethernet (IEEE 802.3u, 1995) designed to carry 100 Mbit/s over four pairs of ordinary Category 3 voice-grade cabling. One pair is always transmit, one is always receive, and the remaining two reverse direction as needed, so three of the four pairs carry data in any one direction using 8B6T (PAM-3) coding. It is half-duplex only and is now obsolete, having been displaced by 100BASE-TX.

PinNameDescriptionTIA/EIA 568ATIA/EIA 568B
1TX_D1+Tranceive Data+Pair 3 Wire 1 white/greenPair 2 Wire 1 white/orange
2TX_D1-Tranceive Data-Pair 3 Wire 2 greenPair 2 Wire 2 orange
3RX_D2+Receive Data+Pair 2 Wire 1 white/orangePair 3 Wire 1 white/green
4BI_D3+Bi-directional Data+Pair 1 Wire 2 bluePair 1 Wire 2 blue
5BI_D3-Bi-directional Data-Pair 1 Wire 1 white/bluePair 1 Wire 1 white/blue
6RX_D2-Receive Data-Pair 2 Wire 2 orangePair 3 Wire 2 green
7BI_D4+Bi-directional Data+Pair 4 Wire 1 white/brownPair 4 Wire 1 white/brown
8BI_D4-Bi-directional Data-Pair 4 Wire 2 brownPair 4 Wire 2 brown

Notes

  • T568A and T568B are the two color codes used for wiring eight-position RJ45 modular plugs. Both are allowed under the ANSI/TIA/EIA wiring standards. The only difference between the two color codes is that the orange and green pairs are interchanged. T568A wiring pattern is recognized as the preferred wiring pattern for this standard because it provides backward compatibility to both one pair and two pair USOC wiring schemes. The T568B standard matches the older ATA&T 258A color code and is/was(?) the most widely used wiring scheme. It is also permitted by the ANSI/TIA/EIA standard, but it provides only a single pair backward compatibility to the USOC wiring scheme. The U.S. Government requires the use of the preferred T568A standard for wiring done under federal contracts.
  • All four pairs are used: one is dedicated to transmit, one to receive, and the other two switch direction depending on the direction of traffic, giving three active pairs in each direction.

References

Category:Networking Connectors