Ethernet 10/100/1000Base-T and 100Base-T4 Crossover
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.
(To
network interface card 1).
(To
network interface card 2).
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.
Note 1: 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).
Note 2: 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 :)
Note 3: The colors originate from the numbering and
name on NIC1.
Note 4: The pinout of this
cable differs from what people usually calls a crossover
cable since all pairs are swapped. If you need
a crossover cable for use with special applications like
serial cables you should not cross the pairs 4/5 and 7/8.