SMC Networks 1255FTX-SC Installation Manual page 13

Cables
Cable Types and Specifications
Cable Type
10BASE-T Cat. 3, 4, 5
100-ohm UTP
100BASE-TX Cat. 5 100-ohm 100 m (328 ft.)
UTP
100BASE-FX 50/125 or 62.5/
125 micron core
multimode fiber
Half duplex
Full duplex
Twisted-Pair Cable and Pin Assignments
Caution: DO-NOT plug a phone jack connector into any RJ-45
port. Use only twisted-pair cables with RJ-45 connectors that
conform with FCC standards.
For 10BASE-T/100BASE-TX connections, a twisted-pair cable
must have two pairs of wires. Each wire pair is identified by two
different colors. For example, one wire might be red and the
other, red with white stripes. Also, an RJ-45 connector must be
attached to both ends of the cable.
Caution: Each wire pair must be attached to the RJ-45
connectors in a specific orientation.
The following figure illustrates how the pins on the RJ-45
connector are numbered. Be sure to hold the connectors in the
same orientation when attaching the wires to the pins.
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Max. Length Connector
100 m (328 ft.) RJ-45
RJ-45
412m(1,351.4ft.) SC
2 km(1.24 miles) SC
10BASE-T/100BASE-TX Pin Assignments
With 10BASE-T/100BASE-TX cable, pins 1 and 2 are used for
transmitting data, and pins 3 and 6 for receiving data. The "+"
and "-" signs in the tables below are used to represent the
polarity of the wires that make up each wire pair.
RJ-45 Pin Assignments
Pin Number Assignment
1 Tx+
2 Tx-
3 Rx+
6 Rx-
Straight-Through Wiring
If the twisted-pair cable is to join two ports and only one of
the ports has an internal crossover, the two pairs of wires must
be straight-through.
Straight-Through RJ-45 Pin Assignments
End 1 End 2
1(Tx+) 1(Tx+)
2(Tx-) 2(Tx-)
3(Rx+) 3(Rx+)
6(Rx-) 6(Rx-)
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.
Crossover RJ-45 Pin Assignments
End 1 End 2
1(Tx+) 3(Rx+)
2(Tx-) 6(Rx-)
3(Rx+) 1(Tx+)
6(Rx-) 2(Tx-)
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