Cables

B-2

B

Table B-1 10/100BASE-TX MDI-X and MDI Port Pinouts

Straight-Through Wiring

If the twisted-pair cable is to join two ports and only one of the ports has an internal

crossover (MDI-X), the two pairs of wires must be straight-through. (When

auto-negotiation is enabled for any RJ-45 port on the switch, you can use either

straight-through or crossover cable to connect to any device type.)

You must connect all four wire pairs as shown in the following diagram to support

Gigabit Ethernet connections.

Figure B-2 Straight-through Wiring
Crossover Wiring

If the twisted-pair cable is to join two ports and either both ports are labeled with an

“X” (indicating MDI-X) or neither port is labeled with an “X” (which indicates MDI), a

crossover must be implemented in the wiring. (When auto-negotia tion is enabled for

Pin MDI Signal Name MDI-X Signal Name
1 Receive Data plus (RD+)
and GND (Positive Vport)
Transmit Data plus (TD+)
and -48V feeding power (Negative Vport)
2 Receive Data minus (RD-) and
and GND (Positive Vport)
Transmit Data minus (TD-)
and -48V feeding power (Negative Vport)
3Transmit Data plus (TD+)
and -48V feeding power (Negative Vport)
Receive Data plus (RD+)
and GND (Positive Vport)
6Transmit Data minus (TD-)
and -48V feeding power (Negative Vport)
Receive Data minus (RD-)
and GND (Positive Vport)
4, 5, 7, 8 Not used Not used
Note: The “+” and “-” signs represent the polarity of the wires that make up each wire pair.
White/OrangeStripe
Orange
White/GreenStripe
Green
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
EIA/TIA568B RJ-45 Wiring Standard
10/100BASE-TXStraight-through Cable
EndAEnd B
Blue
White/BlueStripe
Brown
White/BrownStripe