Korenix JetNet 3705, Руководство пользователя

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Korenix JetNet 3705 Series Industrial PoE Switch User’s Manual 3-4
Power Connections
JetNet 3705 and JetNet 3605f is powered by 48V DC. You should verify that the output of your
DC supply voltage, or AC-DC power adapter, is at 48V DC while under load.
IMPORTANT: The power input range for the JetNet3705 series is from 44v to 57v, but to avoid
damage and keep the switch with good performance, we strongly suggest you choice DC 48V as
the power input.
If you are using an AC-DC power adapter and the DC-IN power indicator (PWR) of the JetNet
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. 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.
Faulty or Loosen Cables
Visually inspect for loose or obviously faulty connections at all connectors and cables. If that
does not correct the problem, try replacing the cable.
Non-standard Cables
Non-standard and incorrectly-wired cables may generate increased network collisions and other
network problems which will impair network performance. A category 5 cable tester is a
recommended tool for every 100Base-TX network installation.
Improper Network Design
Verify that your network has been properly designed. Most errors simply result from poor quality
cable, poor cable routing, network congestion, improper cable length, and too many
repeater/hubs between end nodes. Errors may also result from inadvertent data path loops
(redundant message paths). Message loops can generate broadcast storms that can bog down a
network. There should be only one active message path between any two nodes on a network.
Excessive collisions may be indicative of a cable that is too long. It may also signal the presence
of too many repeaters (hubs) between devices and can also be indicative of a congested
network (too many nodes in one segment).
A high number of undersized and fragmented packets can result from interference induced into
the network cable, by either passing it too close to noisy devices, or because of problems with
the network devices themselves. In these instances, check for improper cabling, damaged
cables, or cables routed too closely to noisy equipment or other wiring.
A high number of oversized packets can result from a bad transceiver, excessive cable noise, or
from a speed mismatch between the switch ports and the connected devices.