Standard wiring for ethernet has two pairs of conductors.
Looking at the connectors:
Pin 1 - Transmit +
Pin 2 - Transmit -
(1 & 2 make a conductor pair)
Pin 3 - Receive +
Pin 6 - Receive -
(3 & 6 make a conductor pair)
Cat 5 cabling in ethernet has two used conductor pairs, and two unused conductor pairs.
