Straight-through wiring, Crossover wiring, Straight-through wiring b-2 crossover wiring b-2 – Enterasys Networks V2H124-24P User Manual
Page 54: Table b-1, 10/100base-tx mdi and mdi-x port pinouts, Figure b-2

Cables
B-2
B
Table B-1. 10/100BASE-TX MDI and MDI-X 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 this switch, you can use either
straight-through or crossover cable to connect to any device type.)
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” (MDI-X) or neither port is labeled with an “X” (MDI), a crossover must be
implemented in the wiring. (When auto-negotiation is enabled for any RJ-45 port on
this switch, you can use either straight-through or crossover cable to connect to any
device type.)
Pin
MDI-X Signal Name
MDI Signal Name
1
Receive Data plus (RD+)
Transmit Data plus (TD+)
2
Receive Data minus (RD-)
Transmit Data minus (TD-)
3
Transmit Data plus (TD+)
Receive Data plus (RD+)
4
GND (Positive V
port
)
GND (Positive V
port
)
5
GND (Positive V
port
)
GND (Positive V
port
)
6
Transmit Data minus (TD-)
Receive Data minus (RD-)
7
-48V feeding power (Negative V
port
)
-48V feeding power (Negative V
port
)
8
-48V feeding power (Negative V
port
)
-48V feeding power (Negative V
port
)
Note: The “+” and “-” signs represent the polarity of the wires that make up each wire pair.
White/Orange Stripe
Orange
White/Green Stripe
Green
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
EIA/TIA 568B RJ-45 Wiring Standard
10/100BASE-TX Straight-through Cable
End A
End B
Blue
White/Blue Stripe
White/Brown Stripe
Brown Stripe