SMC Networks -GT1255FTX-SC User Manual page 42

C
ABLES
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
1(Tx+)
2(Tx-)
3(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
1(Tx+)
2(Tx-)
3(Rx+)
6(Rx-)
32
End 2
1(Tx+)
2(Tx-)
3(Rx+)
6(Rx-)
End 2
3(Rx+)
6(Rx-)
1(Tx+)
2(Tx-)