Description

This article is from the Ethernet FAQ, by James Messer James@NetworkUptime.com with numerous contributions by others.

3.8] What pin assignments are used in twisted-pair Ethernet cabling?

Twisted-pair Ethernet (10BASE-T, 100BASE-T, or 1000BASE-T) uses an
RJ-45 connector, which is an eight-pin modular connector.

       Contact 1   Transmit +
       Contact 2   Transmit -
       Contact 3   Receive +
       Contact 4   Not Used
       Contact 5   Not Used
       Contact 6   Receive -
       Contact 7   Not Used
       Contact 8   Not Used

When looking at an RJ-45 wall jack (female), contact 1 is on the
left and contact 8 is to the right. When looking at the RJ-45
connector on the end of a cable (male) with the tab on the bottom
and the contacts on the top, contact 8 is on the left and contact 1
is to the right.

 

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