Installing the Switch
25
NXA-ENET24 Hardware Installation Guide
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 (FIG. 20).
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.
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.)
10/100BASE-TX MDI-X and MDI Port Pinouts
Pin
MDI Signal Name
MDI-X 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.
FIG. 20
Straight-through Wiring
FIG. 21
Crossover Wiring