B-5
Switch Ports and Network Cables
Twisted-Pair Cable/Connector Pin-Outs
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Twisted-Pair Cable/Connector Pin-Outs
The HP Auto MDI-X Feature.
In the
default configuration
, “Auto”, the
10/100Base-TX ports on the 10/100-TX vl Modules used in the Switch 4200vl
Series automatically detect the type of port on the connected device and
operate as either an MDI or MDI-X port, whichever is appropriate. So for any
connection, a straight-through twisted-pair cable can be used --
you no longer
have to use crossover cables
, although crossover cables can also be used for
any of the connections. The Gig-T vl Module supports the IEEE 802.3ab
standard, which includes the “Auto MDI/MDI-X” feature, which operates the
same way.
N o t e
HP Auto MDI-X was developed by Hewlett-Packard and shared with the IEEE
for the development of the IEEE 802.3ab standard. HP Auto MDI-X and the
IEEE 802.3ab Auto MDI/MDI-X feature are completely compatible.
If you connect a Series 4200vl Switch twisted-pair port to another switch or
hub, which typically have MDI-X ports, the Series 4200vl Switch port automat-
ically operates as an MDI port. If you connect it to an end node, such as a
server or PC, which typically have MDI ports, the Series 4200vl Switch port
operates as an MDI-X port. In all cases, you can use standard straight through
cables.
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. In general, 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-A or 568-B (not USOC). See the Pin Assignment
tables below the cable illustrations later in this appendix for a listing of
the signals used on each pin.
