Digital Loggers

Ethernet Crossover Cable Usage

 
 

Most modern Ethernet ports are Auto MDIX.  When connecting a DLI wired-Ethernet device to an Auto-MDIX port, a crossover cable isn't needed.  If you can access a DLI power controller (see the web page for the product), you don't need a crossover cable.

 

If you are connecting to an older port, or a device such as a router or switch that doesn't support AutoMDIX, you may need a crossover cable.

 

The table below shows the wiring of a crossover cable.  DLI products are 10/100BT so the pairs on pines 4+2 and 7+8 are unused.  It doesn't matter how they're wired.

Two pairs crossed, two pairs uncrossed
10BASE-T or 100BASE-TX crossover
Pin Connection 1: T568A
RJ-45 TIA-568A Left.png
Connection 2: T568B
RJ-45 TIA-568B Right.png
Pins on plug face
signal pair color signal pair color
1 BI_DA+ 3 Pair 3 Tip
white/green stripe
BI_DB+ 2 Pair 2 Tip
white/orange stripe
Rj45plug-8p8c.png
2 BI_DA- 3 Pair 3 Ring
green solid
BI_DB- 2 Pair 2 Ring
orange solid
3 BI_DB+ 2 Pair 2 Tip
white/orange stripe
BI_DA+ 3 Pair 3 Tip
white/green stripe
4   1 Pair 1 Ring
blue solid
  1 Pair 1 Ring
blue solid
5   1 Pair 1 Tip
white/blue stripe
  1 Pair 1 Tip
white/blue stripe
6 BI_DB- 2 Pair 2 Ring
orange solid
BI_DA- 3 Pair 3 Ring
green solid
7   4 Pair 4 Tip
white/brown stripe
  4 Pair 4 Tip
white/brown stripe
8   4 Pair 4 Ring
brown solid
  4 Pair 4 Ring
brown solid

 

You can identify a crossover cable by looking at the connectors.