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CTI 2572 Installation and Operation Guide
85
8.3. Network Communications Problems
Most of the problems you encounter with the Ethernet network data link will probably be associated
with cabling problems. The LEDs on the 2572 can help you locate the problem source. If you are
connected to an active network you should see the Ethernet Receive LED flash. Note that this LED
detects all traffic not just packets directed to module address.
Symptom Probable Cause Corrective Action
The Link Beat LED does
not light when you connect
The opposite end of the cable is not
connected to a hub.
Plug the opposite cable end into
an Ethernet hub.
to the 10BaseT port. The
10bT port is not selected.
The cable is faulty or the RJ45
connector is improperly wired.
Test the cable for continuity and
proper connection. Replace the
cable or re-install connectors as
required.
Substitute a cable known to be
good.
The hub is not generating a link beat
signal.
Some hubs can be configured
for local area networks that do
not use a link beat. Ensure that
the hub is properly configured
and that the power is applied to
the hub.
The Link Beat LED is on
but the Ethernet Receive
LED does not flash
There is no traffic on this portion of
the network.
Check connections to the hub.
Note: Very short Ethernet
frames may fail to light the LED
The Ethernet receive light
does not flash when the
AUI port is active (AUI
Transceiver is being used).
The transceiver on the AUI port may
not be receiving power from the
module. Cabling may also be faulty;
see above.
Note: Very short Ethernet frames
may fail to light the LED
Most transceivers have a power
LED. If this is not lit, check the
AUI Power source switch.
Unless you are using an
external supply or using a self
powered transceiver, the switch
should be set to I
NTERNAL.
The cabling is faulty. Check the cabling and the
connector. Substitute a known
good cable.
The cabling may be faulty or
improperly terminated
Check all connections
thoroughly.
If you are using a hub- based
topology, the hub may be defective.
Check the hub for proper
operation.