B-4
Switch Ports and Network Cables
Twisted-Pair Cable/Connector Pin-Outs
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If you happen to use a correctly wired crossover cable, though, the switch will
still be able to automatically detect the MDI/MDI-X operation and link
correctly to the connected device.
If the port configuration is changed to any of the fixed configurations though,
for example 100 Mbps/full duplex, the port operates as MDI-X only and the
correct cable type must be used: for connections to MDI ports, such as end
nodes, use a “straight-through” cable; for connections to MDI-X ports, such as
on hubs and other switches, use a “crossover” cable.
Other Wiring Rules:
■
All twisted-pair wires used for 10 Mbps, and 100 Mbps operation must be
twisted through the entire length of the cable. The wiring sequence must
conform to EIA/TIA 568-B (not USOC). See “Twisted-Pair Cable Pin
Assignments” later in this appendix for a listing of the signals used on each
pin.
■
For 1000Base-T connections, all four pairs of wires in the cable must be
available for data transmission.
Please see “Note on 1000Base-T Cable
Requirements” on page B-2 for more information on 1000Base-T
cabling.
■
For 10 Mbps connections to the ports, you can use Category 3, 4, or 5
unshielded twisted-pair cable, as supported by the IEEE 802.3 Type
10Base-T standard.
■
For 100 Mbps connections to the ports, use 100-ohm Category 5 UTP or
STP cable only, as supported by the IEEE 802.3u Type 100Base-TX stan-
dard.
■
For 1000 Mbps connections, 100-ohm Category 5E or better cabling is
recommended.
