Cisco Catalyst 2950 Hardware Installation Manual page 134

Diagnosing Problems
Table 4-1 Common Problems and Solutions (continued)
Symptom
Poor performance or
excessive errors
(continued).
No connectivity.
Unreadable characters on
the management console.
System LED is amber, and
all port LEDs are off.
Catalyst 2950 Desktop Switch Hardware Installation Guide
4-4
Possible Cause
Bad adapter in attached device.
• Excessive errors found in port
statistics.
4
STP checking for possible loops.
Incorrect or bad cable.
No link at both ends.
A crossover cable was used
•
when a straight-through was
required, or the reverse.
The cable is wired incorrectly.
•
STP checking for possible
•
loops.
Switch not recognizing a GBIC
module.
Switch not recognizing an SFP
module.
Incorrect baud rate.
Corrupted software.
Chapter 4 Troubleshooting
Resolution
• Run adapter card diagnostic
utility.
Wait 30 seconds for port status
LED to turn green.
For the correct pinouts and
•
the proper application of
crossover vs.
straight-through cables, see
the "Cable and Adapter
Specifications" section on
page B-8.
Replace it with a tested
•
good cable.
Wait 30 seconds for port
•
status LED to turn green.
Refer to your GBIC module
documentation for more
information.
Refer to your SFP module
documentation for more
information.
Reset the terminal-emulation
software to 9600 baud.
Attach a monitor to the serial
port to display the switch boot
loader. For more information,
refer to the switch software
configuration guide.
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