3com 5500-EI Quick Setup Guide

Auto-negotiation problems will occur with 10BASE-T or 100BASE-T 
where auto-negotiation is disabled and incorrect cables are being used 
(cross-over or straight)

Auto-negotiation problems will occur with fiber if:

■

The Receiver (RX) and Transceiver (TX) cable connectors are 
swapped

■

Fibers are broken

■

Auto-negotiation differs at either end (a link appears at the ‘fixed’ 
end and not at the auto-negotiation end)

In the rare event of your switch unit experiencing a hardware failure, refer 
to the list of suggested solutions below.

Your switch has a fan monitoring system that will generate fan failure 
warning messages. Fan failure could potentially reduce the lifetime of the 
switch. The monitoring system polls the fan status at periodic intervals 
while the unit is powered up.

If one fan has failed in the switch, a warning message will be generated 
in the following ways:

■

Unit LED — the seven segment display will show a green flashing ‘f’.

■

RMON Trap — if configured, an RMON trap is generated and sent to 
the management workstation.

■

Command Line Interface — an indication of a general hardware 
failure is provided through the Top level menu displayed when logging 
on to the CLI. For more detailed information about the failure select 
the display logbuffer command.

■

Web interface — an indication of fan failure is provided through the 
Device Summary table for the specific unit. In addition all Summary 
tables turn red to indicate the fan failure.

If a fan failure warning message is generated:

1 Power off the unit.

2 Check that the air vents are not obstructed.