SMC Networks 8124PL2, Installation Manual

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Cables
B-2
B
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.)
You must connect all four wire pairs as shown in the following diagram to support
Gigabit Ethernet connections.
Figure B-2 Straight-through Wiring
Table B-1 10/100BASE-TX MDI and MDI-X Port Pinouts
Pin MDI Signal Name MDI-X Signal Name
1 Receive Data plus (RD+)
and GND (Positive V
port
)
Transmit Data plus (TD+)
and -48V feeding power (Negative V
port
)
2 Receive Data minus (RD-) and
and GND (Positive V
port
)
Transmit Data minus (TD-)
and -48V feeding power (Negative V
port
)
3 Transmit Data plus (TD+)
and -48V feeding power (Negative V
port
)
Receive Data plus (RD+)
and GND (Positive V
port
)
6 Transmit Data minus (TD-)
and -48V feeding power (Negative V
port
)
Receive Data minus (RD-)
and GND (Positive V
port
)
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/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
E nd A
E nd B
Blue
White/Blue Stripe
Brown
White/Brown Stripe