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10BASE-T/100BASE-TX Fast Expansion Module
This Fast Expansion Module incorporates two RJ-45 connectors, one MDI-X and
one MDI. The MDI-X port performs an internal crossover function that allows easy
connection to other devices using standard straight-through cables. The MDI port is
without the internal crossover function, permitting connection to devices having an
internal crossover function using standard straight-through cables. For connection
to 10BASE-T networks, you should use category 3, 4, or 5 cables meeting the
specifications outlined in "Cabling Requirements for 10BASE-T Ports" on page 1-9.
For connection to 100BASE-TX networks, you can use only category 5 cables.
100BASE-FX Fast Expansion Module
This Fast Expansion Module incorporates two ST connectors. Use 62.5/125-micron
multimode optical fiber that meets the specifications in TIA/EIA 568A or ISO/IEC
11801. The maximum length of optical fiber cable between devices should not
exceed 2000 m (6561 ft) if the link is being operated in full-duplex mode. If operated
in half-duplex mode, the length should not exceed 412 m (1352 ft).
Cabling Requirements for the Management Port
The management port is a standard DB-9 male connector that provides an EIA/TIA
232-E (was RS 232-C) serial interface. You can connect locally, with a null-modem
cable, or remotely, over telephone lines, using serial cables and modems at each
end. Once connected, you can manage the 8237 and upgrade microcode. This is
sometimes called out-of-band management.
You can make a null-modem cable by connecting a null-modem adapter to a
standard serial cable.
Cabling Requirements for Stack Link
The 8237 Stack Link ports provide an RJ-45 connection for the Stack Link cable. A
0.5 m (1.6 ft) length cable is provided with each unit. If a longer cable is needed use
only straight-through 100-ohm category 5 STP cable with RJ-45 plugs on both ends.
Note that the total length of the Stack Link cable must not exceed 75 m (246 ft).
Protected Vital Configuration Data
The following configuration information is stored in nonvolatile memory and will
survive a power outage:
The above are retained for all models. In addition, the following information,
arranged by function, is retained for Model 002 and Model 003:
1-12
8237 Hub Installation and Planning Guide
• System name and location
• Segment to which the hub is connected
• ID number assigned to the hub
• Password assigned to the hub
• SYS group
MIB II system contact group
MIB II system name
MIB II system location
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Table of Contents
Troubleshooting
