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4
4
Chapter 4
Troubleshooting
This chapter includes some information for general troubleshooting as follows:
Power Connections
Incorrect Connections
¾
Faulty or Loosen Cables
¾
Non-standard
Cables
¾
Improper Network Technologies
LED Indicators
Power Connections
This unit is powered from 12-48V DC. You should verify that the output of your DC supply
voltage, or AC-DC power adapter, remains within the required 12 to 48V DC range while under
load (it should be capable of supplying at least 6W of power for this model).
IMPORTANT:
Never exceed 48V DC or you will damage the switch.
If you are using an AC-DC power adapter and the DC-IN power indicator (PWR) of the switch
does not light when the power cord is plugged in, you may have a faulty power cord. Check for
loose or broken power connections. Also check for power loss or power surges at the AC power
outlet. Verify that your AC-DC adapter is properly sized and outputs the correct voltage under
load.
Incorrect Connections
Select Ethernet cables with specifications suitable for your application. In general, Ethernet
cables are categorized into unshielded twisted-pair (UTP) and shielded twisted-pair (STP) types.
Shielded cables are recommended. In general, category 3, 4, and 5 Ethernet cables are suitable
for systems with 10Mbps transmission speed. But for systems at 100Mbps, you should only use
Category 5 or better Ethernet cables. Gigabit ports should use Cat-5 or Cat-5e cables for
1000Mbps connections. In addition, always make sure that the cable length between device
ports does not exceed 100 meters (328 feet).
The RJ45 ports of this switch automatically detect straight-through or crossover cables and then
cross-connect the transmit and receive channels when you connect the switch to another device.
This feature does not apply to the fiber port connections. You must manually cross-connect
transmit and receive cables between the fiber ports of connected devices. For fiber connections,
make sure that the fiber cable type matches the fiber model (multi-mode or single-mode).
For the RJ-45 connectors, use the correct UTP or STP cables as required. For 10/100M ports,
use 2 pairs of twisted cables. For Gigabit 1000T ports, use 4 pairs of twisted cables. If the RJ-45
connectors and cables are not correctly connected, the link will fail and the green LNK LED will
not light.
