UNICOM Electric 8 - Manual (Page 63)

7.
Troubleshooting
This section is intended to help you solve the most common problems on
the SmartGST801M.
Incorrect connections
n Faulty or loose cables
Look for loose or obviously faulty connections. If they appear to be
OK, make sure the connections are snug. If that does not correct the
problem, try a different cable.
n Non-standard cables
Non-standard and miswired cables may cause numerous network
collisions and can seriously impair network performance.
n Improper Network Topologies
It is important to make sure that you have a valid network topology.
Common topology faults include excessive cable length and too
many repeaters (hubs) between end nodes. In addition, you should
make sure that your network topology contains no data path loops.
Between any two ends nodes,
there should be only one active
cabling path at any time. Data path loops will cause broadcast storms
that will severely impact your network performance.
Diagnosing LED Indicators
The switch can be easily monitored through panel indicators to assist
in identifying problems. The LEDs indicate common problems you
may encounter and where you can find possible solutions.
If the power indicator does not turn on when the power cord is
plugged in, you may have a problem with power outlet or power cord.
However if the Switch powers off after running a short time, check for
loose power connections, power losses, or surges at the power
outlet. If you still cannot resolve the problem, contact your local
dealer for assistance.