Twisted-pair cable and pin assignments
159
Pin
MDI-X signal name
MDI signal name
8
-48V
-48V feeding power (Negative
Vport)
Note: The plus (+) and minus (-) signs represent the polarity of the wires that make up each
wire pair.
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 autonegotiation 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.
Straight-through wiring diagram
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 autonegotiation 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.
SMB
Using the Nortel Business Ethernet Switch 50 Series
NN47924-301
01.01
Standard
1.00
October 2006
Copyright © 2006, Nortel Networks
Nortel Networks Confidential
.
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