Ethernet 10/100/1000Base-T and 100Base-T4 Crossover

From HwB

Also known as Crossed Network cable

This cable can be used to cascade hubs, or for connecting two Ethernet stations back-to-back without a hub. It works with 10Base-T, 100Base-TX, 100Base-T4 and 1000Base-T. Use a good enough cable, if you are confused about categories of cables then use category 5e(nhanced) and you'll be fine even at 1000Base-T.



RJ45 MALE CONNECTOR to network interface card 1.


RJ45 MALE CONNECTOR to network interface card 2.

(1000Base-T names in parentheses)

Name NIC1 Color NIC2 Name
TX+ (BI_DA+) 1 White/Orange 3 RX+ (BI_DB+)
TX- (BI_DA-) 2 Orange 6 RX- (BI_DB-)
RX+ (BI_DB+) 3 White/Green 1 TX+ (BI_DA+)
- (BI_DC+) 4 Blue 7 - (BI_DD+)
- (BI_DC-) 5 White/Blue 8 - (BI_DD-)
RX- (BI_DB-) 6 Green 2 TX- (BI_DA-)
- (BI_DD+) 7 White/Brown 4 - (BI_DC+)
- (BI_DD-) 8 Brown 5 - (BI_DC-)

That means that the white/orange cable connected to NIC 1 pin 1 should go to NIC 2 pin 3 and NIC 1 pin 2 to NIC 2 pin 6 etc.


  • It's important that each pair is kept as a pair. TX+ & TX- must be in the pair, and RX+ & RX- must together in another pair. (Just as the table above shows).
  • While 10Base-T and 100Base-TX only uses 2 pairs, please connect all four since 100Base-T4 and 1000Base-T needs them and save yourself some future debugging :)
  • The colors originate from the numbering and name on NIC1.



  • IEEE Std 802.3, 2000 Edition