100Base-T4 uses all four pairs. 100Base-TX only uses two pairs.
 (At the network interface cards/hubs)
 (At the cables)
RJ45 FEMALE CONNECTOR at the network interface cards/hubs.
RJ45 MALE CONNECTOR at the cables.
| Pin | Name | Description | 
|---|---|---|
| 1 | TX_D1+ | Trancieve Data+ | 
| 2 | TX_D1- | Trancieve Data- | 
| 3 | RX_D2+ | Receive Data+ | 
| 4 | BI_D3+ | Bi-directional Data+ | 
| 5 | BI_D3- | Bi-directional Data- | 
| 6 | RX_D2- | Receive Data- | 
| 7 | BI_D4+ | Bi-directional Data+ | 
| 8 | BI_D4- | Bi-directional Data- |