Quick Start Manual
Model EN308
TC
 Ethernet Hub Installation Guide
Troubleshooting Information
Symptom
Cause  Solution
Amber Col LED 
blinks.
There is data collision 
on the network.
Data collision is normal on Ethernet networks. No 
action is required.
Amber Col LED 
blinks excessively.
There is data collision 
on 
the network because 
the network is 
extremely busy 
or defective devices 
are connected on the 
network that cannot 
detect network traffic 
or collision.
Make sure connected devices are operating in half-
duplex mode. The hub is not compatible with devices 
that operate in full-duplex mode.
If you suspect that there might be a defective device 
on the network, disconnect devices one at a time to 
isolate the defective unit on the network.
If the network is extremely busy, you may have to 
segment the network with an Ethernet switch such as 
a NETGEAR Ethernet switch or to upgrade your 
network to Fast Ethernet operation.
Wrong or miswired 
cables are used.
Make sure the correct UTP cables are used. See the 
tables in the installation section of this guide for cable 
use and Normal/Uplink push button information. Note 
that home telephone cables can cause a collision 
condition and cannot be used in place of UTP cables.
Link/Rx LED on 
front panel or Link/
Rx green LED on 
rear panel is off 
when a cable is 
attached.
The port is not 
detecting a 
successful link.
Check for a bad cable, cable pairs that are not 
correctly wired, or loose connectors. Make sure that 
there is power to both the hub and the Ethernet 
transceiver on the connected device.
Link/Rx LED on 
front panel or Link/
Rx green LED on 
rear panel is not 
blinking when there 
is data 
transmission.
The port is not 
detecting data 
transmission.
Check for a bad cable, cable pairs that are not 
correctly wired, or loose connectors. Make sure that 
there is power to both the hub and the Ethernet 
transceiver on the connected device.
Green Rx LED on 
the BNC port is not 
on when the port is 
connected.
The port is not 
detecting a 
successful link.
Make sure that each segment is terminated with a 
BNC 50 
Ω
 terminator at both ends. Check for a bad 
cable.
Green Rx LED on 
the BNC port is not 
blinking when there 
is data 
transmission.
The port is not 
detecting data 
transmission.
Check for a bad cable or loose connectors. Make 
sure that there is power to both the hub and the 
connected device.
Troubleshooting Information










